Question
currently have lawn completely dead.  What is the best way to prep ground for new sod (St augustine).
ben
Jacksonville fl

Answer
Land preparation for new sod is focused on facilitating root growth. You want the roots of the sod pieces to grow downwards in the prepared soil. Three things are necessary.
1. Tilth to depth of three to six inches.
2. Organic matter.
3. Water.
A piece of sod will live on a concrete slab if it is given adequate irrigation; its roots will grow laterally and the grass might even retain its green color. But you will always be able to pick it up and walk away with it. A piece of sod will exist on unprepared ground if given enough water; it will root in eventually but in the meantime it will lose condition and be under stress from pests: both plant and animal. A piece of sod, under the best of conditions, will die very quickly if it is not provided with water.
Tilth is the breaking up of the soil into small enough pieces which will permit roots to ramify it but at the same time allow it to retain its structure and not run together and become compact. A rotavator will do this in one operation. A rototiller will do this in a number of passes in different directions. Long ago and far away I used to achieve the same goal with fork/shovel and machete; but the labor was intensive. Rent a rototiller and work the area in different directions until the soil "pieces" get to the size of popped corn. The moisture in the soil will determine how well this goes. Too dry and the whole thing turns to dust; too wet and large clods will result. Most of the time you will have to give the soil some time to dry out before you do the next pass. What can I tell you? It is a matter of trial and error.
Organic matter is supplied in the form of materials like compost, good topsoil and brand-name products like "Milorganite" and "Black Kow". Ideally, you should try to apply it before you do tne final pass.
It is pure wisdom to line up reliable watering before laying the sod.