A Discord auth system

Hey I want to make a system where I can log in with discord, that way get their discord username stored in my database. so I can make a system that auto add them to their rank on discord when I put their rank on the website.

I just do not think I can find any guides or info about it. so is here anybody that can help. or point me in the right direction . i look at sociallite but dont seems i can get it to work.

Sry for pore english.

Best regards Dann