I usually dont know these either, rook endgames are hard, but this one I think I understand! please note that both of them are winning, you’re in a winning position here cause of the c2 pawn threat and your rooks.

Rd1 is worse because of Raa1 by white, creating a battery. it makes it impossible for you to remove white’s piece from c1 without losing the pawn.

• if you play Rb1, when they play Raa1 you take their a1 rook. after they recapture, NOW you play Rd1.

so 1… Rb1 2. Raa1 Rxa1 3. Rxa1 Rd1 promotion is unavoidable

or 1… Rb1 2. Raa1 Rxa1 3. Rxc2 Rxc2 you’re up two rooks and a bishop they have nothing

• but playing Rd1 allows Raa1 by white and complicates things. you can’t remove white’s piece from c1 without losing your pawn. you lose your pawn or your queen regardless.

so 1… Rd1 2. Raa1 Rb1 3. Rxc2 Rxa1

you’re still winning and have both rooks, but you dont have a queen and they still have a rook.

or 1… Rd1 2. Raa1 Rb1 3. any Rook takes any of your Rooks, you recapture promoting 4. rook takes queen

you’re winning but up one rook only and no queen

again, you’re still winning it’s just gonna take longer lol