Ah, yeah, they're still working on it...
In settings, go the bottom and use "Report Problem". Something like "Where is help?" would be a good place to start.
The help page here does include some help on the apps but it is very out of date. For example, it tells you that the app does not work on touch screen phones.
(https://support.chess.com/customer/en/portal/articles/1444928-installing-the-mobile-app)
I downloaded the app on my Android, can someone please post a link to INSTRUCTIONS on how to use it? Thx.