How to give a reference to the server?

Hello every body.

I want to create a board game. So I created pawn (not really possess) for each client. But I want that every player can move their pawn but which weren’t visible by other client. And when every client press a button name “next round”, I want that the server update the movement for all pawns created or moved and can display for the other client.
I know that I need to use the “Set actor replicates” but I don’t really understand why this function doesn’t work. It seems that the server doesn’t recognize all pawns created on the board.

Any idea for my issue?
Thanks in advance !