I'll explain it in a short way, a more detailed explanation will follow within the next days.
There will be a league subdivided in Divisions. In this league clans are able to challenge other clans and improve their ranking. The highest Divisions will have a bit different system.
The cup (tourney) system will work like this:
We announce cups -> clans are able to register during a registration time -> then a tourney tree will be published and the matches dates set -> clans play

There will be several types of cups, like friday night cup and so on.
Currently we haven't decided yet if there will be a kind of "Single instant games", because we hope that the ingame ranking system will handle this.
Hopefully this helps you. As I said, the complete explanation will follow within the next days.
Greetings