I'm trying to edit a layer but it won't let me it just says change costume 1 how do I turn this off so I can edit it again. How do I get rid of the key code so I can edit again??

You probably set Mouse 1 (left click) to the Costume 1 toggle by mistake (it was a common bug).
Go into the custom key binds on the main screen, and if that's the case just reconfigure that keybind to something normal.

Is there a picture guide on how to do that because I don't know how to do that I'm still new to this program.