the system is a pyramid of leagues. these are part of the same system through the idea of promotion and relegation. the better clubs in each league go to a higher league. the clubs that finish the season at the bottom of their league can go down to a lower league. promotion has two important factors. the first factor is how well the club plays. the second factor is that the club needs to meet criteria set by the higher league. these criteria are often about having the right facilities and finances.