Both white and black have a few fighting methods at their disposal with which they can fight for a win or draw. This is an inventorization of the possible fighting methods.
Meaning of the arrows:
Blue = 1st, 4th move
Green = 2nd, 5th move
Yellow = 3rd, 6th move.
Red = moves of the enemy.
Despite the wellknown advice to put your rook behind a passer, the rook is much more active on c3 where it puts pressure on c7 and can attack the kingside pawns or assist the defense of the white pawns.
What white wants to do is to bring his king to the black kingside pawns and nibble them away.
With the pawnsac c5, black opens the fourth rank so he can keep the white king at bay with Ra4 while maintaining the pressure against a3.
Blacks king cannot leave c6 because of the push of the c pawn towards promotion.
Black should always be aware of the danger of a rook trade, since that leaves him with a lost pawn ending. So the pawn on c5 is tabu due to the skewer Rc3.
White can abondon his queenside pawns as long as he can remove all three black pawns and is left with two connected passers.
White to move.
White must be aware of tricks that leaves him with a sole rook pawn. So he must not play the immediate Rxh5 here, but he must play Ke3 first to avoid the double attack Rf3+
I'm sure there are a few more fighting methods. I will update this post whenever I stumble upon them.