That is already set up in the link above:
SpawnLocation is an array that hold placeholder actors just to get their location. So if you have 3, it will get all 3 and update the int array accordingly.
Since the int array is same size as the places where you want to spawn your clases, it will loop and execute once per location.
Here notice I added % node → What this does is that no matter how many places I have to spawn weapons, it will never go out of bounds. Just make shure that when you add / remove classes from the select, update the number accordingly.
Finally this spawns and adds a reference to an array just in case you want to do anything else.
All you have to do is populate the SpawnLocation array:
Updated the link with all the nodes: