The one who sees - and women are exempt from sanctifying the moon, since this is a positive commandment caused by time. And although women are accustomed to do all positive commandments caused by time and make a blessing over them, in any case they don't need to do this mitzvah, since they caused a blemish in the moon. And a blind person is obligated in sanctification of the moon, since this blessing was established about the renewal of the world, and they also benefit since others see and lead them on the path, and this is like "yotzeir hame'orot" [first blessing before the morning Shema], so wrote the acharonim. And see the Biur Halacha. And a minor, when they are educable, we educated them about it [so written in the name of רי"ע, and seems that this is only Rabbeinu Tam, in chapter עיי"ן, but for Rashi there it's not obvious, and is similar to saying Shema; see there - and it's possible that his intent was also that it's good to practice this way ab initio, like is decided there in the Shulchan Aruch about saying Shema, see there].

Only at night - excluding at dusk, when the moon is partially visible but it's still daytime.

And we benefit from its light - that is, at the time that its shining is visible over the earth. If the moon is covered with clouds, if the cloud is thin and weak so that the moon is seen from within it and it's possible to benefit from the moon, bless, and if the cloud is thick, do not bless. And if one begins to bless and then the moon is covered by clouds, finish the blessing, except in the case where one estimates that the moon will be covered by cloud in the middle of one's blessing, for in this case one shouldn't begin the blessing. And see Biur Halacha, and this is the ruling of there is a screen dividing one and the moon - the ruling is this too, like clouds, that if the screen is translucent so that one benefits from the moonlight through it, and it's possible to see things in the light of the moon, one can bless over it, and if the screen is thick and one does not benefit from the moonlight, do not bless over it, for that would be a blessing in vain, and see what we write at the end of the siman.

We do not bless, etc - this is the best fulfilment of the mitzvah, and when one concludes בהג"ה [?] and it's written in the Maggid Meisharim sefer that this sign should be in your hand for the month, that you should bless the blessing of the moon on motza'ei Shabbat, you will find success. And when it is covered and hidden and you are unable to bless it, that month will not be successful, God forbid.

Only on motza'ei Shabbat - this is also the case for motza'ei Yom Tov.

But if it's after that - he means to say that motza'ei Shabbat night is the 11th night [since the molad], one should not wait, lest it be covered in clouds for four nights, since after that etc, and according to that which is written in saif 3 in the note of the Rema, one needs to canclulate if there will remain five more nights until half of day 29 hour 12 chalak 793 since the molad.

Nice clothes - we are now not accustomed to be particular about this.

Before Tisha b'Av - since we exist in a state of mourning.

Before Yom Kippur - for here too we are terrified of the strength of the Judgment and do not exist in a state of joy; see the Biur Halacha.

But not on motza'ei etc - that we don't exist in a state of joy, and we bless on the days that are after it instead. And it's explained in the D"M [?] that if Tisha b'Av falls on a Thursday, one should wait until motza'ei Shabbat which is the 12th day of the month.

Or other fasts - such as, if one doesn't sanctify in Tevet until the fast, one cannot sanctify after the fast, but should wait until the next night which is the 11th of Tevet. And in any case if it happened in Adar that one did not sanctify until Ta'anit Esther, the Taz wrote that one can sanctify after the fast, since the time would otherwise run out. And behold, all of this is according to the opinion of the Rema, but the opinion of the acharonim in all of this was that we sanctify even on motza'ei Tisha b'Av, and all the more so with any other fast. Rather they wrote that one must break one's fast beforehand, and on Motza'ei Yom Kippur since we are joyful to go out in freedom, we sanctify even before breaking the fast. And on motza'ei Tisha b'Av one needs to be careful not to sanctify barefoot. And regarding the matter of when a mourner should sanctify: the belief of the Magen Avraham is that if they will completed their mourning before the tenth of the month, they should wait and sanctify on the night of the tenth. But if their mourning is completed on the 14th of the month, they should not wait for the night of the 11th - it's better to sanctify the moon in the midst of mourning. And the belief of the Ba'al Sha'arei Efrayim is that one should wait to sanctify until completing their mourning; they should wait, unless this would cause them to miss the time entirely, in which case they are able to sanctify whilst in mourning, and can go outside to sanctify, and see the Biur Halacha.

That Yom Tov fell on - and all the more so that we don't sanctify it on Shabbat night, and many reasons were stated about this according to the Kabbalah. And in any case, if one didn't sanctify until Shabbat and Yom Tov, and the time would pass, it's certainly permitted to sanctify even on Shabbat and Yom Tov, even alone, and that is also the view of the poskim.

And looks... and says... - It's written in the Shiurei Knesset haGedolah that this means to say, it appears that before completing the whole order he hangs his eyes on it, and so is the general custom, but hear from the name of the Sefer Charedim which was extremely strict about this to prevent gazing at the moon, and only permitted gazing at it before the bracha itself was completed. The Magen Avraham in the name of the Shlah was even stricter, that even during the bracha one should not gaze at it, rather look at it once when they want to bless and after that should not look at it.

And dance, etc - the acharonim wrote that one should be very careful not to bend one's knees to dance, in order not to seem like one is bowing to the moon. Rather, one should lean on ones toe's and dance (i.e. jump?).

And backwards: "like a stone" - and the Magen Avraham wrote in the name of the Mateh Moshe that some say the entire pasuk, until "You have acquired", and then again backwards.

And should say to one's friend, etc As if to say, since one first said "should fall, etc", one should say to one's friend "Peace be upon you" [Magen Avraham] see Magen Avraham, that he mentions many verses which there is kabbalah to say them and they have not been printed, since they are already written in seder kiddush levana and all are accustomed to say them.

From the day of the molad - not specifically from the day, rather we count the time of the molad, that it from this time we count 29 days from evening to evening (ie 24-hour periods), and if so, when the molad is in the middle of Monday, it's permitted to sanctify in the night of Tuesday, although there is still not 15 days from evening to evening.

And the 16th is not included - that since the 15th day, each day the moon lessens, and there is no renewal here.

Except until half, etc - that this exists for us, that there is no renewal of the moon in less than 29 days 12 hours and 793 chalakim of an hour [that an hour is split into 1080 chalakim], and if so, if the molad begins on motza'ei Shabbat 2 or 3 hours into the night, it is forbidden to sanctify it in two more weeks at the beginning of the second night, according to the Rema, even though 15 full days are not yet completed.

Until 7 days pass - And the majority of the acharonim disagreed regarding this, and according to them in any case after 3 days from evening to evening from the time of the molad [i.e. 72 hours], that we already benefit from its light, it's possible to bless regarding it, and one should not leave the mitzvah to sour [i.e. delay] - if so, if the 3rd day of the month is on a Sunday, it's correct to wait until the next motza'ei Shabbat. And according to that which was explained in saif 2 in the note, and many acharonim (of whom the Gra was one) were lenient regarding this, and thought that it's inappropriate to delay the mitzvah in any case, and for this reason the person who is accustomed to behave this way has on whom to rely. Particularly in the winter when it's rainy, certainly the person who is eager to sanctify behold they are praised.

Under a roof - rather, under the dome of the heavens. And the reason is that sanctification of the moon is like greeting the face of the Shechina, and this is not honourable to stand under a roof. For this reason, we exit from under the roof to the street, the way one would go to greet kings. And in any case all of this is only lechatchila, but one who has any worry that they would be unable to go outside, such as the place being unclean or living amongst non-Jews, should sanctify in their home via a window or an open door by the moon.