Second year gardener looking for advice enriching sandy hillside

I have an 1/8 acre East facing hillside in zone 7a that is very neglected. It is not very steep and I put in a couple of raised beds into the hill last year. Permaculture seems confusing to me. I would like to turn the half acre hillside into a more sustainable long term food garden. The soil is sandy and compacted and there are a few oak tree stumps. I am afraid of erosion because of the trees that were cut down there last year. I was thinking of sheet mulching around the raised beds in the hopes that I could turn the whole area into rich soil for planting. If I was to lay down overlapping cardboard then some compost and say 4 -6 inches of new straw would that be enough? Would it be better to skip the straw and plant some kind of cover crop to use as a soil builder?
I have plans to add a hugelcultur there as well. I didn't realize until now that I should have started in the fall with this.
Any suggestions would be greatly appreciated.