You have doubled rooks on the b-file and a bishop bearing down on c8. It’s hard to find a mating possibility, but all this power focused on the king still gives you the upper hand; your threats may be enough to allow you to push your opponent’s pieces around, especially his king, and thus create a tactical opening. Start in the usual way by looking for checks. There's just one: Rb7+. The king has to leave the seventh rank and can’t go to the sixth, so Black plays it to d8. White naturally might like to mate by dropping his rook down to b8, with the thought of then playing the other rook to b7; but Black's knight on c6 guards b8, and anyway the king would be able to slip away onto e6.
The important thing is to avoid being discouraged by the failure of the mating idea and to focus on the side effects of the Black king’s movements: as it jumps around to escape checks, it may move on and off of lines occupied by its other pieces and so create chances to take them. Thus when Black plays Kd8 he moves his king onto the back rank with its rook at h8, which is loose. White thinks of dropping a rook onto the same line for a skewer. First the skewering square must be examined, and we see that Black guards b8 with his knight. But we know that when you have doubled rooks you can use the first to exhaust the enemy’s defensive resources and then follow up with the second; so White plays Rb8, and after Black plays NxR White has RxN+, reestablishing a rook on b8 with nothing more Black can do in reply except move his king and allow RxR.
An initial lesson of the position is something we have seen once or twice before: you don’t always have to get behind the king to skewer it; skewers along the back rank also are possible. You also can see here an illustration of the varied powers of coordinated rooks. First one of them provides cover for the other, forcing the king from the seventh rank down to the eighth; then one is sacrificed on b8 to clear the way for the other to take its place, giving the skewer.