If you have followed the advice of @switchingsocial and are trying @GIMP after previously using Photoshop, you might find the different paradigms confusing.
If you get stuck how to do something, use the GIMP tag on graphicdesign.stackexchange.com to find an answer quickly:
https://graphicdesign.stackexchange.com/questions/tagged/gimp
The docs also have some useful tutorials for common tasks: