Detour - Basic Concept

So, as i'm learning more about pointers and their functions, i decided to take a look at some detours on some bases. Can someone experienced please tell me if this is right, a detour simply tells the anti-hack to scan at an address before where we entered by saying "Address Where we entered - value". Is this correct or could somebody please explain it a little more clearly to me because i'm still a bit confused.

Your wrong.
A hook is replacing original code with a jmp instruction in asm.
Its jumping to your code, which gets executed then by the game. The hing is, it returning the original code pointer, so you can call the orig code easily out of your hook. Very simple..