Building a Hugelkultur Bed

I made a sort of hugel bed a few years ago after cutting down an old, diseased apple tree. Dug down a foot, threw in the apple tree and other assorted bits, topped up with the soil then made a lasagna bed on top of that. Haven't had many problems with it other than having to top it up every year because the soil level sinks. Not really noticed many benefits either. It's a lot of work to make one and I wouldn't bother again.