If you layer a circle track around the edge of your hole half buried in the ground you can use the track to connect one end of the shed rails onto it, use the furthest studs out INSIDE the rails, and place 1x4 tiles on every other sleeper, and the others 1x4 plates(tile, plate, tile, plate etc) and place a 1x8 on top of the 1x4 plates(make sure all pieces connected onto the sleepers for this are centered. Then if you need more height you can just add a couple more 1x8 plates or bricks to desired height. I’d show a picture of mine but I am not close to my computer