What's your plan and where do you think you are headed?
If you stayman, partner not surprisingly bids 2♦.
Part 2 - We have a 3♥ bid that shows a 6-4 Major hand (either way), GF+. After the auction 1N-3♥-3NT-4♣-4♥, you find that partner has no major Kxx or better, and a heart preference. Take it away.

Help

1NT (12+ - 15) - ?
Usual expertish agreements in place (Smolen, Texas, etc)