FM18 Editor

Hey! I'm new with the editor. So could you give me a hand? I want to create a structure to Polish league (fictitious).
Well.. there will be two groups. In one group will be 10 teams in second group too. Four of the best team will be promoted to the champions play-offs. Six of them will be relegated to play-offs of relegation. I want to make it like normal league (with 2 rounds). I'm newbie so could you help me?