Can someone explain this puzzle?

defensive resources are important but sticking to the fundamental tactical motifs provides more “bang for the buck”

On move 45 Rb6, white is attacking the pawn on b4.
On move 46. ... Nf3, black is attacking the rook on g1
On move 47. Rg3, is the only safe square the rook can move to, and keep up the threat of mate on the g-file. (47. Rg2 allow black to move his knight with a discovered attack on the rook on g2 from the Bishop on e4.)
47. ... Qe7 sets up a forced mate that runs several moves if white doesn't avoid it.
48. Rf3 white is trading his rook for the knight, presumable to permanently axe the threat of a Queen+knight mating net.
48. ... Bf3 positioning the bishop try and hamper the opponent's king's movements. At this point the game became much more drawish.
https://chesspuzzle.net/Solution/222133
I'm a little confused, I don't understand the purpose of neither black nor white's moves and was hoping someone could explain them.