I started building some raised beds in 2020. Did 2 4x12' beds that year. Changed design some and built 2 3x12' and 1 3x8' bed last year. This year I am working on 4 3x12' and 1 or 2 3x8' beds. I've got 3 built and hope to fill them tomorrow, at least get started.
I put down a layer of cardboard to knock down any grass and weed compitition. Then a layer of chicken wire to keep the moles out. My beds are 2' tall, so I fill the first 1' with old wood, limbs, stumps, whatever is handy. It'll rot out in years to come and become good rich dirt, plus the rotting wood helps hold moisture better. On top of that I load the beds the rest of the way with mushroom compost. They have produced well so far. Just a learning curve since I want to over plant and crowd too much in the beds. I got a little better last year and will space things out even better this year.
I've already planted one bed this year. Couple weeks ago I put out about 4' of bed with carrots, about 3' with parsnips, 2 small areas with peas, and 6' of bed with yukon gold potatos. Also scattered some radishes around. And in December I had lined one side with garlic. Garlis is doing great (also have it growing in 2 other beds along the edges), radishes are coming up and I saw a couple peas poke thru today. I also planted a bed with asparagus last year, today I saw the first 2 nice thick spears pop thru. We'll get to eat 2-3 messes from the bed this year. Next year should be wide open for 6-8 weeks.
I've already got me seed on hand for this year, seed taters just waitin, and first batch of onion slips waiting to go in the ground.