ik i am a dumb. but pls help
In case all you want is to add an entry to the BossesDefeated list, you don’t need the “Set” node in the end because the “Add” node is doing all the work already. “Set” nodes are used when you want to fully (re)initialize a variable of any kind. You don’t want to touch anything that’s already in the BossesDefeated list, you just want to add another entry.
This should fix the error, which is most likely just “Array inputs must have an input wired into them.” (and should have appeared in the “Compiler Results” tab at the bottom). For future reference, I’d be great if you could also screenshot the actual error message to help us help you.
Also, unrelated to the error, you could simplify the blueprint using this:
(and also, it’s usually recommended to use the Name type instead of String whenever possible; in short, for performance)