Ive used switch on int but doesnt works
Did you feed a Random Integer in Range value into the Switch on Int?
Random Integer in Range as lukefwilson said, but i think “Select” node is better instead of switch set Integer type as input and Class as output, you can change pin types by right clicking there should be option to change, i also think Wildcard pins set type whatever you plug to, and plug class output to class input of Spawn node