Pick only the first instance of a for loop

I have this function setup to change a slot from one type to another :

At the moment it picks all instances of slot0 that are "empty". How do I adjust the logic so that it picks only the first slot0 it finds in the ascending order?

Thanks

Also feel free to suggest a completely different method if I am doing this entirely wrong.

You should be able to call Stop loop after Set...

blackhornet haha cheers! I was trying to stop it using a condition, never used Stop Loop