The code wouldn't be all that simple, it depends on how muck work you have done already and how you want it to look.
If you have a working GUI system and want to select character's with button clicks then that should be fairly easy.
If you want something like the old-school character selection menues you would have a set of boxes with images of them and move some cursor among these when the player presses the arrow keys or WASD keys or what have you.
For some RPG-like character selection screen you might want to line objects representing each one up in a line and then use
dbPickObject to select one by clicking on the objects on-screen.
"Why do programmers get Halloween and Christmas mixed up?" Because Oct(31) = Dec(25)