Clothing and Armour directly changes the appearance of your Player Character,
with Armour being always worn over Clothing. Both Clothing and Armour have no
statistics and are only used to dress up you Player Character.
To equip Clothing or Armour press I to open the Inventory. Then click on any Item
of Clothing or Armour with the Right Mouse Button and click on Equip in the
appearing Context Menu.
Alternatively after opening the Inventory (I), press O to open your Equipment.
Now click and drag any Item of Clothing or Armour from your Inventory to the
associated highlighted Slot in your Equipment and release.
Your Player Character will immediately equip an Item. To unequip Clothing or
Armour, open Equipment (O), click an Item of Clothing or Armour with the Right
Mouse Button and click Unequip. Alternatively drag an Item of Clothing or
Armour from Equipment back to a slot in Inventory (I).
Note that to change Clothing or Armour, you will need to be Out-of-Combat.