How to spawn 2 seperate characters using mulitplayer

Hey guys.
So yesterday i figured out how to put my project in a LAN multiplayer system. It works perfectly so far.
But when i spawn (press play) it spawns only what character the game is set to use as player 1.
How would i set up a custom spawn system so when the 2 players spawn they are 2 seperate characters of my choosing? And possibly how can i set up a button in my menu to choose what character you would like to be for the session? Thanks in advance!!!