Can't recommend this approach highly enough: have someone with minimal expertise go through your docs with the goal of achieving the goal of the docs. Sit next to them or screenshare. Do not speak to them, certainly do not help, just watch. Watch them fumble. Watch them not know what to do. Watch them experience things you (the author) didn't, because you already had xyz configured on your machine and you forgot user…
Watch someone play the game for the first time. Don’t interfere. See if they can figure out how to play.