M:tg players around the world sign up, or signed up, at dci, got a player registration number, and after each tournament the results were uploaded onto the platform for the purpouse of creating a system that assigns players rank. Is there something like that in A:N? Do I have to sign up someplace to get a number?

There is no current ranking system for Netrunner. You just go to an event and play.

I am not sure how it is for Netrunner regional but for X-wing I think you have to win a local tournament in order to get a place within the regional scene. Winning a regionals I think gets you a spot at worlds.

Correct me if I am wrong at all I have no experience with these official tournaments. (I have yet to win a tournament.)

For Netrunner, a Store Championship gets you a super-bye at a Regionals (basically for one round you count as winning but don't actually play, and it also counts for your Strength of Schedule).

If you win a Regionals, you get the super-bye for Nationals (as well as a guaranteed place in the Swiss - in the UK at least Nationals is 2 days, and the first day is a qualifier). Win at Nationals, go to Worlds.