Problems with multiplayer game

I’m trying to create a multiplayer game, but I have 2 problems, the first is that even following everything in the YouTube video of the creation of a multiplayer game, the players and also player 1 don’t move, the second is that I can’t open 2 windows to test the game.

When I start the game the players don’t move, not even player 1

I don’t know how to get the players moving.