cInput 2 is a commercial release and is not free.
If you're reading this manual then most likely you have already purchased a license for cInput. If you don't already have a license, you can get cInput 2 from our website or from the Unity Asset Store.
We tried to keep the price low so everyone can still afford it. If for some reason you cannot afford the price you can use Custom InputManager 1.x which still works fine.
If you really need to use cInput 2 and can't afford the price then contact us to explain your needs and we'll see if we can work something out.