How can i learn my user name?

I created a new character on PS4 and I can't quite understand what i'm supposed to use as my username.
I probably missing something very obvious, but I would be really thankful if someone could help me

you can use any combination of letters and numbers you want, just no spaces, marks or other symbols

By my first message I meant that I can't understand what to use as username to log in on "Planetside 2 players" site.
When you first start your game on PS4 it only lets you create your character, but not an account which would tie your character to this site.