on Mobil there isnt a back button. I almost didnt play this game cause I couldnt figure out to exit certain menus. Then I noticed the double tap worked. It also opens your menu in mobil. I feel like this is what they are asking.
I just wish there was a back button when using items. I've had at least three magic apples accidentally given to ryen when trying to double tap out of the menu
Double tap on top of two non selected characters. If one of them is selected instead of backing, repeat with other 2. You most certainly have 4 slots for members to click on at all times, meaning you have a lot of space to safely double tap to back.