What do you grow?
Dig a hole, or if you know some one, borrow /rent a post hole digger.
Make a hole at least two feet, three is better, and see what is down there.
If it rains, see how long it takes for the hole to dry, IF it drys.
How big is your garden?
You should heavily till it at least once just to break it up, that twill also raise the level for while.
If you can get some one with a plough and plough once then till that.
Add mulch , hay/straw bales, leaves veggies the grocery store is tossing, coffee grounds from coffee houses and till that in.