A prism has two identical bases, top and bottom; a pyramid has one base and a single pointed apex. Change the number of sides on the base and see how the structure changes.
Prisms and pyramids are both solids with a polygon base, but they're named differently based on how many bases they have. A prism has 2 congruent polygon bases, top and bottom, connected by rectangular side faces. A four-sided prism is actually built exactly like the rectangular prism you already know.
A pyramid has only 1 base, and every side of that base connects through a triangular face up to a single point at the top. Just picture the classic pyramid shape. If the base is an n-gon, both a prism's side faces and a pyramid's triangular side faces will number exactly n.
Move the slider to increase the number of sides on the base one at a time, and see what rule the number of faces, edges, and vertices follows as it grows.