Answer to Question 1
The ice was produced in shallow clay plates, about the size of a saucer. The water in these clay plates wept through the clay. This water dampened the small straw mats holding the clay plates in racks a few feet above the ground. The straw aided with evaporative cooling of the water. Under the right conditions a thin film of ice would form overnight on each clay plate.
Answer to Question 2
First evidence of man making ice appeared more than 3,000 years ago, about 1000 B. C.