Apple Music profile setup issue on iPhone and iPad

i'm switching to apple music and when i downloaded the app to my phone there was a screen saying set up a profile i accidentally pressed ''later'' now i can't find the option to view or set a profile through my iphone or ipad only my computer. when i press my profile i cannot change my profile's @ or name or profile picture. i don't even have an @ though. when i try to delete the profile it says a problem occured.

[Re-Titled by Moderator]