A hand is part of a player's body used to create or improve clay items. Select a hand (shown in the player's Character window in the lower right corner), right-click a lump of clay, and create either a bowl, jar, or flask.
Weapons and other items can be equipped in a hand by dragging the item onto the character's held item slot (Character window - (left) or (right) held item - on each side, second from the bottom). Weapons can also be equipped by right clicking them and selecting Equip. The player will automatically hold the weapon and attack with it.
Weapons in the right hand will attack faster than a weapon in the left.