First dynamic cloth which you should test is not rendo freebie, but cloth plane from Poser primitives.

Load cloth plane and ball (hi or low res) from library. Place plane over ball, create new simulaton, clothify plane, select collide again ball and ground and run simulation. After few second or minutes you will understand how cloth room works.

Later try to change simulation setting "cloth self collision" and later change simulation parameters fold resistance, cloth density etc.