There are four sequences that lead to 2NT, that then automatically invoke Puppet continuations.. 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+ invitational
  4. 2 opening and a 3NT rebid following  a negative 2 response showing 25+-usually to  play  
  5. 2-2HSN   
  6. 2NT jump 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!

3         Transfer to Hearts   Shows a 5+ card Heart suit. 2NT bidder rebids 3 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.