Lesson
White to move. Main line: 1. Rb7 Kf8 2. Ra8#
One rook cuts the king off on the seventh rank; the other delivers check on the eighth. The king can never approach the rooks because each one protects the rank the other needs.
The full technique from the middle of the board is the same idea repeated: check on one rank, slide the other rook one rank further, and if the king ever attacks a rook, shift it to the far side of the board with the cut-off intact.
It looks trivial — and it is the foundation for every rook ending you will ever play. The animated version makes the alternating pattern obvious in a way a diagram cannot.