Checkmate with a Rook: Essential Endgame Techniques

Let's start by making a box

We Have made a box by pushing our rook to f4

we will oppose the King with ours and make the box smaller

when we reach a situation like this and give a check 

we will keep repeating the same process

Until The king is forced to the back rank

Then we will follow knight opposition to the king

AND...

Mate!