As a fellow Floridian, I can relate to how vastly different things are here compared to many of the experiences people post here from much colder northern climates. Their summer vegetables are our winter vegetables. Full sun plants there might not survive or produce well with full summer sun here. Burying smaller pieces of organic matter just breaks it down very fast and any nutrients get washed through our sandy soil with the large amount of rainfall we get.
I strongly recommend checking out
The Green Dreams YouTube Channel. This is a real Floridian doing real permaculture, and his videos are very dense with information of things that do or don't work here. He is almost exactly the same latitude as my property but on the opposite coast, so I find his information to be extremely helpful. I am super fortunate to have found land with some slope to it, but I'm currently living in Jacksonville at the beach, so I understand being on very flat ground and some of those issues. We get tropical storms that can dump 10"+ in a day and that is fairly common to happen at least once in a year, sometimes much more.
In my garden I made rows and dug between them to pile up my rows higher than the surrounding area. Even with hugelkultur, our soil never freezes and the biology can be so active that things break down fast. This means flat ground with logs added will become flat ground again. I would make certain to start in a high spot, or dig out other high spots to build up the soil in the selected area. If the area is low and you bury logs then it will eventually flatten out where it can get drown by a storm and kill plants. My friend made his first garden in a low spot in his backyard and we got hit with back-to-back tropical storms of 10"+ before hurricane season started. He lost a lot of plants and built up the area to avoid future disaster. There is also the possibility of what is mentioned in the
Jack Spirko article linked above where relatively dry logs freshly buried would become bouyant in a flooded area and destroy the hugel. It might not have a hill to slide down and damage things, but losing the hugel would be a lot of labor lost.
Given how fast things break down in the soil I wouldn't put small woody material in the ground. Anything an inch or smaller would deteriorate quickly and wouldn't be worth the effort of having to re-dig so often. A huge problem here is evaporation. Putting that small woody material on top of the soil as mulch helps keep the sun off and retain moisture. Bare sand in the sun becomes so dry it gets hydrophobic. I believe it causes static electricity below 10% soil surface humidity which causes polarized water molecules to be repelled.
If you see a hot dry patch of bare sand, you can hit it with a hose for several minutes without any of the water soaking in! It seems counterintuitive since sand drains water so quickly, but when baked dry by the sun it repels water.
I really can't stress the mulching part enough. I don't remember which podcast it was, but I remember Paul saying something to the effect that if you have enough mulch to cover 8 acres of land with 1" of mulch or 1 acre with 8" of mulch then you will do better to cover the small area with more mulch. Another lesson I learned the hard way. Anything less than 4" out in full sun with no protection will get pushed around by wind and rain, providing only a small amount of water retention. You could take the idea above and replace acre with any unit of area measurement. Even 1 square foot vs 8 square feet. Having 1 square foot with a single awesome plant would likely be a better experience than having 8 plants struggling to survive.
The last thing I will touch on is soil amendments. Because of the way the sand will drain nutrients through quickly, I wouldn't waste the energy to bury or till in any amendments. Actually I did and had mediocre results. You can put it on top and mulch it which gives it a little further distance to go before washing below the root zone. Even better is to just put it on the mulch so it gets absorbed and slowly released. Something like compost tea given regularly will help keep nutrient levels up. It might be a bit of work, but certainly no more than tilling year after year. It is pretty easy to get fungi growing here with the high humidity during the rainy season. This can help to break down some of the mulch on top and release nutrients to the soil at a steady rate. Not too wet, not too dry, proper nutrition, and mother nature can provide the rest.