Creation Kit: Spawning an item when the player reaches a certain level

[p4ck3tl055]

I'm trying my hand at the creation kit - to support my let's play story.  I need a courier's note to spawn in the courier's container upon the player reaching a certain level.  In fact I'd like to have multiple events like this, at different levels of course.

 

I've got the courier working and delivering the first note, but I've got it set to happen upon the game starting, which of course means that it happens immediately.  I need to know how to change this so it happens after the player reaches a certain level.

 

If needed I can upload my esp file somewhere - it's only got the single encounter in it.

 

If anyone could show me an example, or point me in the right direction, I'd really appreciate it.