How to reset an ipad to factory settings?

I have an iPad that my elder brother send to me and for sometime now i have doing things on the iPad that i can even remember(in short in don’t even know). Now i am stocked in a point where i think my iPad can be destroyed or the iPad doesn’t look good to me. The big question i have now is; I need to know how to reset an iPad to factory settings so that i am able to have the iPad the way it was sent to me before use so that i can start learning how to use it step by step.
