A jump shift shows either:

1. 15+ with trump support
2. 15+ and a good suit
3. 19+ and a balanced hand.

Opener usually re-bids their suit, then responder bids:

1. a new suit showing a fragment (a 2 or 3 card suit) thus showing a splinter in the fourth suit
2. re-bidding their suit
3. re-bidding NT