Larian Studios Forums Divine Divinity (English) General Divine Divinity. The game addicted.

You need to left click an equipped item with charm slots in order to use the Enchant Weapon skill. That will open a new window showing the number of slots (the 'Charm Quality' of the item), with the number of open slots being determined by the level of Enchant Weapon (if the charm quality is higher than the skill level, there will be an X through some slots).