The concepts are still the same. GIMP suohld have most of the same features, but the way that you go about doing them in GIMP will be different. If you understand enough about GIMP to know what equivalent actions you'd have to take in GIMP rather than Photoshop (for example, if I say to make a new layer, as long as you know how to make a new layer in GIMP), then you suohld be able to follow it.Unfortunately, I know nothing about GIMP, so I can't help you beyond that. :(Good luck!