John Gill Commentary Numbers 33:12

"And they journeyed from the wilderness of Sin, and encamped in Dophkah." — Numbers 33:12 (ASV)

And they took their journey out of the wilderness of Sin
According to the account in Exodus, this was after they had the manna given them, see (Exodus 17:1)

and encamped at Dophkah ;
twelve miles from the wilderness of Sin; and of this, and the next encampment, no mention is made in Exodus.