ונסע...אהל מועד...בתוך המחנה. Between the two flags which have already been mentioned.

כאשר יחנו, as soon as half the camp had arrived at the next destination the Tabernacle would be put together again so that it would again be situated in the center of the entire encampment. This was possible as the Kehatites traveled immediately behind the flag of Reuven’s segment of the army, and they had been transporting the vital contents of the Tabernacle. We know from Exodus 25,22 that these parts of the Tabernacle were the essential ones, as G’d had made His communicating with Moses dependent on the presence of these furnishings. It follows that the meaning of the words כאשר יחנו can also be understood as “as soon as they (these parts) would come to rest.” The Tabernacle whether in its functional form, fully erected, or in its pre-fabricated parts only, always remained in the center of the Israelites whether the latter were on the move or encamped.

והלוים לא התפקדו, also among the total of the remainder of the tribes.

כאשר צוה ה' את משה. As G’d had said in 1,49 “do not count them as part of the Children of Israel.”