The analysis board loads an engine but shouldn't actually make the moves.
setting up positions for analysis for mobile versions of chess.com?


Are you asking about the site on the mobile browser? Or the app?
On the browser it is Play > Analysis on v3


Yeah, Computer > Custom and before you hit start, turn both black and white to human players.
The other way to get to an analysis board is from a game.

When doing puzzles in books or playing through annotated games, I used to press "Computer" and do "custom set up" under "analysis" mode... now it seems that I can still set up a custom position, but I am forced to play the computer rather than play through my own or an author's variations. Did the mobile site lose this functionality in a recent update? Please help. Thanks.