That is, as I understand it!
There are 4 groups of Segunda B....the teams finishing 1st, 2nd, 3rd and 4th in each group qualify for the promotion play offs.
For the sake of clearness lets say :
Group 1 : Teams A, B, C and D.
Group 2 : Teams E, F, G and H.
Group 3 : Teams I, J, K and L.
Group 4 : Teams M, N, O and P.
The Champions of each group enter a draw (A, E, I and M) and the resulting two ties (home and away) have two winners, who are promoted (lets say E amd M get promoted). The 2 losers from these (A and I) are still in with a chance.
The other 12 sides go into a draw, and 6 ties come out. The resulting six winners plus the losers from the champions round (A and I) make 8 teams. From these 4 ties are drawn (always home and away), another 4 teams are eliminated, leaving 4. From these you have 2 ties, the winners joining E and M getting promotion.
So in total 4 sides are promoted.
Clear? Thought not.....