rook and two pawns vs rook

King makes a journey to f6 then rook blocks the check (if black gives a check an pawn g6 is then winning). Computer can help you.

after 1. kg6 rc8  2. kf6 rf8+ if the king tries to stay out of the pawns way in order to advance g6

3. ke6 or e5 doesn't matter rf1! and black starts berserking checks from the first rank.

Here's an endgame tableabase, it shows how white is winning: https://syzygy-tables.info/?fen=6k1/4R3/7P/2r3PK/8/8/8/8_b_-_-_0_1 

That's trivial actually.

You just have to push that pawn to g6, so you can just start with 1.Kg4 and Black's checks do not last for long.

The only case it can become difficult is when the pawns are advanced too soon, but it's still a win. You can use the following position as a good exercise: white's winning method is no rocket science, but not that easy, either.

This position is almost identical to one in The Torture Book on Rook Endgames (official title: "Understanding Rook Endgames" by Mueller and Konoval). 

What you need to remember is that pushing the pawn to h7 is not recommended. This creates all kind of stalemate tricks with the black king on h8. Objective is to push to get h6 and g6. This will make the black rook passive because of the mate threat. Then you can go for the rook trade. For example: 

1. Kg6, Rc6+; 2. Kf5, Tc5+; 3. Kf6, Rc6+; 4. Re6, Rb8 (if 4. ... Rb1, then it's mate with 5. Re8+, Kh7; 6. g6+, Kxh6; 7. Rh8#); 5. g6 (key move), 5. ... Ra8; 6. Rd6 (although pushing h7 will work too here, but it's bad technique in my eyes, as it will spoil the win so often in different positions); 6. ... Rf8+; 7. Ke7, Ra8; 8. Rd8+ trading the rooks and winning the king and pawn endgame easily.