Groundsheet
Groundsheeta are made in a variety of waterproof material. If the groundsheet is built-in,it should extend at 10 centimeters up the tent walls.
Fabric
Most tents are made of cotton or nylon. Cotton"breathes",so you do not get condensation inside the tent,but it is usually heavier and more expensive. It also stretches and shrinks with changes in the weather. Nylon tents are often cheaper,but nylon does not "breathe" as readily, so tents must have air vents.