I live just north of Dallas, TX and go some St. Augustine Sod installed Friday (3 days ago). I saw them till the yard, lay the sod, roll it, then water it in. I was waiting for them to give me instructions, but all they did was drive off leaving me with no info on how to take care of it.
I know that for the first couple of weeks i should keep it "moist", so Ive been watering it every 6 hours for 20 minutes each watering (timer for 6AM, noon, 6PM, midnight).
Is this enough?
Should i fertilize? When? How much?
I have lawn guys that mow every other week and they are coming a week from tomorrow. Is it safe for them to mow at that time?
Just realize you have a plant transplant product. Your initial goal is to keep the sod layer alive until it sends down roots into the soil so more frequent watering may be necessary to start. You do not want to water so much you compact the soil under the sod to the point you end up just growing a sod layer for eternity (surprisingly common especially with clay soils). You want to taper off and water less frequently and more deeply as soon as you can. There is no magic formula and you just have to keep an eye on it adjusting for your climate and how it is doing. If in doubt, you can explore the situation with a garden trowel.
The sod should have come from the farm well fed and freshly harvested. It would not have hurt to put a starter fertilizer in when prepping the soil but if you did not, I would wait a month and then start in on a regular lawn maintenance regimen. You do not want to risk a fertilizer stress or burn situation to the tender roots.
The more you can stay off the sod until it bonds with the soil and establishes roots the better. Remember you just have a spongey layer of roots and grass blades on top of soil right now. Again, the danger is compacting the soil underneath it so the roots have trouble getting into it. Or squishing the roots dead. Your lawn mowing people probably will not hurt it but if it could go an extra week without being mowed and looking like it was scalped, you could skip the service once. You do want to mow for good health though.
Eventually you will want to water as infrequently as you can get away with and longer so the water goes deeps. The roots will follow it. Again, you have to adjust for climate but a starting point is to strive for the equivalent of 1" rainfall per week.