Weapons and armor don't do anything yet, so all you can do with them is go to where they are sitting and pick them up. For items that do have uses check the rules page to see what they are. Assigning an item to anyone really doesn't do much either as of yet since anyone can pick up an item and walk around with it.
To EQUIP items on to your character, you want to be in the Position screen, and use the Items button on the left. You can't put them on your character and set them for use in the Inventory screen.
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"May the Grace of Ara go with you, and His Vengeance be wrought upon your enemies."