John Gill Commentary Numbers 1:54

"Thus did the children of Israel; according to all that Jehovah commanded Moses, so did they." — Numbers 1:54 (ASV)

And the children of Israel did according to all the Lord
commanded Moses
Pitched their tents by their own camps and standards; did not come near the tabernacle but kept at a proper distance from it, and did not meddle with things they had no concern with, and which were peculiar to the Levites:

so they did ;
which is repeated to show how readily, punctually, and perfectly they observed the command of God with respect to this affair.