I spent about 15 minutes reading about the competition prior to our first game. From what I read, it isn't that complicated.
My understanding is that there are 4 levels or tiers (calling it a league just muddies the water) and there are then groups within those levels. Finish bottom of your group and you're relegated to the level below. Win your group and you are promoted to the level above AND are into a knockout competition for a place at the Euros against the other group winners at the same level. 4 levels = 4 spots the the Euro finals.
I think it is reasonably well thought out and means that at least one of the bottom ranked nations will be at the Euros.
Now time for someone to tell me I've missed something, and if only it were that simple.