Northeast here. Layed cardboard down, then chunks of wood from yard cleanup, then brush on top, next leaves dry and green, a little soil, topped with fresh mulch inoculated with wine cap mushroom mycelium. 3 more the same way but as raised beds. First year I did pack them with so many plants and I had a whole ecosystem going on with their own micro climates. Had them now for at least 7 years and every fall I put leaves from the yard into it to overwinter. I also keep a compost pile for yard debris and kitchen scraps that in spring I top the beds with a bit of compost and cover with new mulch. I don't water as much as I should probably but I've learned packing plants tighter then "normal" spacing works best for holding water and microclimates. Also giving the hugel leaves for minerals every year and adding a bit of compost before adding more mulch is key. The raised beds soil deep as these are 3.5' high is beautiful and I can vertically garden in perfect soil.
Biggest lesson though is do not allow any weed or flower propagate in it as they will infiltrate every part of that hugel! I let moonflower grow in one and although it's beautiful it wraps and strangles other plants and it's a battle, I've tried weeding it out, just made more, I tried suffocating it by adding cardboard and layers over it, grew right through it, I tried digging all the roots out, calmed down but didn't get them all.
Winecaps do great and it's like an Easter egg hunt every year finding them among my plants! I also have two beds that get covered with bird nest fungi, cool and weird looking, and this year I plan on adding oyster mycelium to the beds and see how that goes.
Some years I felt that there may be a nitrogen issue and not sure because I added mulch without enough compost under those years? However I amended it by adding green debris without seeds to the beds. Here and there as I putter around the yard little by little.
