How do I set up an item to trigger a journal entry when it's picked up?

Do you have MWSFD?

It's very helpful - the first tutorial explains how to make a script to do what you want

Begin my_first_scriptIf ( OnActivate == 1 ); here we will enter what happens when the chest is openedendifEnd

Except for picking up an item you would want it to read

Begin my_first_scriptIf ( OnActivate == 1 )    Journal "My_Journal" 5 ;where 5 = whatever journal index entry you want addedendifEnd

Alternatively you could have a greeting set which checks to see if you have the item - it would need a unique Id - then if you are carrying the item someone can greet you and recognise the item you have and in the results box you would add Journal My_Journal 5

Awesome, thank you very much.