When you have your materials ready, use a flat shovel to remove the sod from your intended site and level the soil so your bed rests on level ground. Then you are ready to work. A drill driver makes the work go much faster as you drive the wood screws home. You may want to get some mesh and some stakes to hold it to keep the wildlife looking for salad greens out of your beds. If you wish to get fancy, you can mix your compost with good, black topsoil from the garden store half and half. You can add other ingredients to lighten the soil too, but we didn't bother and it is working out fine.
A word to the wise, toss aside your need for perfection in this experiment. Perfection and backyard gardening are not going to mix well. No matter how hard you try, you can't manage how those seeds are going to sprout and grow. Just enjoy the results with satisfaction.
Hey, and if you want to grow potatoes, take an old, plastic garbage can, fill it to an appropriate depth, after drilling some drain holes in the base, with soil, and plant. What could be simpler.
Today, on our 31st wedding anniversary, my wife and I harvested our first heirloom radishes. It was nice.