So the way it should be set up, the button you press should execute a custom event. The ‘Target’ part is just set up automatically and I did that in the First Person Character, so its fine having its target to the name of your own blueprint!
You should be able to press a button still, as that will take the input from a client and then the RPC will execute it on the server.
As the component replicates, just telling it to execute that function on the server will mean the changes made will be reflected on clients.