There are four sequences reaching 2NT, that then invoke Puppet. These are:
  1. 2NT opening bid showing a balanced 21-22
  2. 2 opening and 2NT rebid showing a balanced 19-20
  3. 2 opening and a 2NT rebid following a negative 2 response showing 23+
  4. 2NT response to a T-O Double

All Puppet responses to 2NT are transfers except 3 which is a stayman like inquiry for both 5 & 4  card majors.
Primaey objective is that the 2NT bidder always plays the final contract. To achieve this responder always makes transfers:

3 Inquiry:  preferable requirement is 3+ cards in each major. However 2 cards to a top honour is acceptable. Responses are:
3!         No 5 card major but holding at least one 4 card major (possibly both). [Note some variants use 4 to show both majors this is both unnecessary and potentially dangerous as it takes bidding beyond 3NT.]
3      Natural. Shows the 5 card major bid
3NT       No  Major  so  NT bidder is  3-3 or 3-2 in the majors

After a 3 reply 3 bidder now bids as follows:

3!             Shows  a 4  card 'Spade' suit
!              Shows  a 4 card 'Heart' suit
3NT            No 4 card major
!             BOTH Majors

Now for the transfers, there are no jumps or other deviations!

You may come across additional bids (extensions), however the Author finds them unnecessary.
Continuations may proceed to game OR directly 4NT ERKCB OR cue-bidding. Following cue-bids TURBO 4NT operates.