How do the Step 3 and 4 play-offs work?

Non-League's restructuring means ‘Super' play-offs are set to take place at Step 3 in the next few weeks while two Step 4 play-off winners also won't be promoted.
Those were two of the key outcomes following last summer's Pyramid shake-up, which saw an extra division added at both levels in an attempt to cut down on travelling. The FA have announced their plans for the second phase of the restructuring – read more here.
There will be three clubs relegated from each of National League North and South – Nuneaton Borough, Ashton United and FC United of Manchester have been relegated from the North while Weston-super-Mare and East Thurrock have fallen through the South trap door so far.
That leaves six spaces to fill at Step 2 from the four feeder divisions at Step 3.
The champions of all the four Step 3 leagues go up, but there is only space for two other sides from across the four divisions.
The traditional play-off structure from second to fifth place remains, but the winners won't be guaranteed promotion. Instead, the four successful teams face a ‘Super' play-off – two separate ties, decided by the FA Leagues Committee on the most suitable geographical basis.
The matches will be one-leg and played at the side with the best points-per-game ratio during the season. The two winners will be promoted to Step 2.
The extra Bostik League division at Step 4, taking the total to seven, has also complicated things numbers-wise. There will be 12 promotions spots to fill and seven will be taken by the respective champions.
That leaves a handful of places up for grabs – and they will be allocated to five of the seven divisional play-off winners.
The five with the best points-per-game ratio will win promotion from Step 4. It means two sides who win their divisional play-offs will suffer the heartbreak of not going up.
Teams who finish in the lower play-off positions at the end of the regular season but then go on to win them are less likely to go up on the points-per-game ratio basis.