Backtracking question

Someone please explain the concept of Funky Chess Board ptroblem

You have a knight and you need to count the maximum no of locations you can visit inside the board keeping in mind that you cant visit one cell again during traversal. Concept here is backtracking you can go to block(in the manner knight moves) mark it visited and increase the count. During backtracking you can again unmark the visited cell. Hope it helps!