How do I use "Activated Spells"?

In the world of magic, you will find that there are certain spells that:

• You must activate independently, or
• Will trigger on its own when something happens.

If the spell in question is one of the former, you must indicate that you are using the spell by clearly saying “Activate” at which point the spell will take effect and will proceed normally. If it is the latter type spell, such as a spell shield, it will be triggered and expended once a certain event takes place (i.e. being hit with an appropriate spell when you have a spell shield active.)