1) The upper left is a weight, and mousing over it tells you how much your equipped items weigh.
2) The lower left is a body. Right clicking on this pulls up a context menu. The two items of note on the menu are [[Karma]] and [[Inventory#Profile|Profile]]. This is where you manage them.
3) The lower right is a hand. Clicking or double clicking on it will allow you to use your hands as a tool. This is useful for creating pottery items.