Basic problem with cast magic package

[Kratius]

I want to use a 'cast magic' package so I've looked it up but there's still something I don't really understand;

In the locations tab I need to put where the NPC is meant to cast his spell.

In the target tab it is said in the found info that I need to specify which spell should be casted (under 'object') but as far as I can see there I only can select objects... Where can I specify which spell must be casted?

 

Let's say I want an NPC to go to Xmarker01 and when reached the location he needs to cast 'THCshield' on himself. How to do that? Xmarker01 selected in Location, and then? How can I make sure the NPC casts THCshield on himself? When I go to the target tab I can't find where to select that spell (only statics can be seen...).