Did you take delivery of the sod and then lay it a week later or did you put it down the day you received it? Makes a big difference. It could have gone dormant (if you are lucky) or it could have died from smothering in that time. Zoysia is the most tricky of all the turf grasses. It might go dormant early in the summer and remain dormant no matter what you do until the following spring.

Any suggestions?

1. Yes be concerned. This is what happens when sod stays on the pallet for too long. It has smothered or gotten a disease. For smothering all you can do is work it back to life. The underlying roots are probably not dead, but the tops are. Zoysia does not bounce back quickly so be patient. If it was a disease, it will probably not live through the winter, so just watch it carefully now. With winter dormancy coming quickly, there is not much you can do that will really help. You could apply a fungicide but you'll not know if it worked because the lawn will go dormant about the time it starts to look better. 2. This happens all the time but it should not. Maybe Lone Star Grass is not the place to buy sod. 3. Not correct. At that rate you'll flood the grass and soil underneath. Let's hope and assume they rolled the sod down. What you are doing by watering is trying to get the roots to knit into the underlying soil. That only requires moisture, not mud. Instead water it for 10 minutes 3x per day. Breakfast, lunch, and dinner are perfect times. Then back way off. In the winter you will not need to water more than once a month. In the summer you will ramp back up to watering an inch (or so) per week. How much you water in the summer depends on shade, wind, humidity, soil type, grass height, density and maybe something else. I watered no more than 5/8 of an inch per week this past summer. 4. Keep an eye on zoysia. At the first sign of the grass not looking right, watch it like a hawk. As I mentioned above, zoysia does not rebound quickly from a disease or insect experience. Why did you decide on zoysia rather St Augustine or bermuda, which account for 99.99% of the turf in Texas?

The term "topsoil" is meaningless because all that "topsoil" is is the top 4 to 6 inches of soil from someplace. Sandy soils, in Florida or anywhere else, tend to drain really well and they do not retain much soil moisture so unless the soil was amended well with organic matter, which will aid in moisture retention, your grass may not have enough water to grow. To root well grasses need 4 to 6 inches of a good soil, well endowed with organic matter, that is evenly moist but well drained.