Q.Sod
I bpuhht sod on a Friday installed it on Sunday, Monday it turned brown as though it went dormant or is dead
What do I do now?

The browning of your new grass may be due to drying out during the transportation, time lag before planting two days later, or inadequate water after planting. Or if you applied a chemical fertilizer prematurely it could cause a burning.
Water it now until muddy wet. Use a roller borrowed or rented for that purpose, or tamp it with the back of a steel rake to insure contact and merging with the underlying soil. Water it daily for a week or even two or three times a day if it's hot and dry weather.
Give it a couple of weeks to respond. If it doesn't start to put up new green growth withing a month, start over, and don't let it dry out next time. Keep it moist and tarped during transport ad storage; preferably plant it and water it as soon as you get it home.