There are a few different ways of organising the RKCB responses and follow-ups. Here is a simple one that is also not too far from optimal, at least from an I/A perspective:-
5 of trump suit is a sign-off opposite 0-2 key cards; a queen ask opposite 3-4 key cards; a king ask opposite 5 key cards
1st non-trump step is a queen ask opposite a 14 or 03 response; a king ask opposite a 25 response
2nd non-trump step is a king ask opposite a 14 or 03 response; a specific suit ask (SSA) opposite a 25 response (with NT replacing the most expensive suit)
3rd and 4th non-trump steps are SSAs (with NT replacing the most expensive suit)
5th non-trump step is a SSA opposite a 14 or 03 response; asks for something extra opposite a 25 response
Some additional rules:
If you have a known 10 card fit, show the trump queen even if you do not have her.
When showing the trump queen, be sure to show a side king at the same time.
If partner explicitly asks for kings and you have all of the remaining unaccounted for, you can afford to bid above 6 of the trump suit.
If your known trump fit is only 8 cards and partner asks for the trump queen and then continues after you deny it, they have extra length and are hoping you also have extra (to make a 10 card fit).
SSAs are a rare but powerful tool. There are many ways or organizing responses - one is: trumps = no 3rd round control; 1st step = doubleton (Jx or worse); 2nd step = Q; 3rd step = K (3 or longer suit); 4th step = Kx doubleton; 5th step = singleton; 6th step = KQ.
You can find (much) more detail by looking up Kantar's 2004 write-up, which is available online for free at
Bridge with Dan.