How to get a specific character as server

Hi, I want to make the server attach an actor to one of the Clients, for that I need a reference to that specific character. I tried making a RunOnServer function that has a ReferenceToSelf as an input but that doesn’t seem to work. Can someone please help me, I posted this question 2 times on the answer hub with 0 replies and I am sure there is a way to do this.

every client pawn has a copy on the server, if you want to attach actor to a client, you need to attach it on server and make sure that actor are also replicated(with either default movement component or a movement component that you can set to replicated.)
post you BP graph as simple as possible and then we can see what went wrong.