The action library has a large list of interactions you can do with other players, and quick commands for yourself. The quickbar above it is usually in the upper left of the screen. It can hold these commands, and also weapons/tools for easy use. You drag the desired command or item to the numbered slot you want to use, then when you hit that number it autoequips or uses the command listed. There are several pages to this, so you can change them with the arrows or the F1-F9 keys, this allows you to setup multiple quick-keys for use in varried situations. Interaction is for other players or items you find ingame, as well as the newly added taming. Misc holds autorun and other useful commands. Emotes are where you will find poses and my favorite the dances. Pet contains the new list of pet commands for an animal you have tamed.