It's really fun! Click and hold on tha lasso tool to get the magnetic lasso, for selecting things easily. Hold down shift to add to the selection, alt to take away. the little buttons on the bottom of the layers bar go things. The first one is the layer styles (outer, inner glow, shadow, bevel, etc.) and the trash is to delete selected layers. One of them adds a new layer. Under Filter---> filter gallery you can see a preview of all the filters you can do to it.
Those are what I think are the most important, and the help is useful. Hope you have fun!