Hello i am creating a bookshelf with the (Creation Kit Tutorial Bookshelves) (sry for my bad english).
but in this steps...

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4. Next, find the trigger called "PlayerBookShelfTrigger" under WorldObjects>Activator. Expand it to a decent size by pressing "2" and dragging the arrows.
Note: The standard size should encase all of the book markers, but it is not necessary.
5. This trigger will need to be linked to the container as well. Leave the keyword blank. Under the Primitive tab, make sure that the Collision Layer is: "L_TRIGGER". Hit OK and that should be it.
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i can't see on the trigger any "primitive" tab between "3d Data" and "Ownership" tabs.
The trigger is also invisible and i can't expand it or resize it. Please help me.

You can find triggers with the primitive tab when you click Create Trigger button (button with the T) at the top of your window.