How to store things in multiplayer

Hello
(sorry for my mistakes I don’t speak english very well)

Would someone be kind and explain me in detail how I can do in a multiplayer to display the username of a player above is head and let everyone see the good pseudo for everybody ?
I tried a lot of things (more than i can count) and nothing is working at all and I am starting to lose hope.

Many people explain me many things about this subject but i wasn’t able to understand and i am totally lost. So I would like to start all over again with an easier subject that is just display the pseudo of the player above his head.

What I have for the moment :

  • you launch the game, it asks you your password and accound name. It compared what your give in a database on a server. (And this is working well) And if the password and account name are correct, then it give me the username (different from account name). All this things happened in my UI_login, the user interface for the login.

  • Then, it ask me if I would like to join or create a game. In my test i always have 3 players (1 server and 2 clients) because in the future I would like to delete the fonctionnality of create a game and the only possibility will be to connect to a dedicated server. But nevermind. And then it launch the map

  • So, to go back to my UI_login, when the server gave me the username of the player i decided to store it in my game_instance since I haven’t any player state yet (player state is created later, when we open the map)

  • When the game begin, in my player blueprint i display his username above his head with a text render. I do the following thing to do that.

I know that when the player join he will not be able to see other player with the right username, but for the moment I just would like to make himself see him with the right username (it will be a beginning…).
The result for the moment is :
Player one sees his username well and sees nothing above the head of other players
Player two sees nothing on his head and nothing on other player heads.
Player three sees nothing on his head and nothing on other player heads.

Thank you for your answers !
Kind regards