The responder shows support after a level 1 opening bid
Apply the law of total tricks ! The number of trump cards you hold matters more than your HCP :
Simple raise to the 2-level. With at least 3 cards in the Major and 5-9 HCP. With 3 cards support and 10-11HCP, give preference to a 1NT forcing bid...
Limit raise at level 3 With 11-12 HCP and 4 cards.
2/1 then support.
at level 4 With 13-14 HCP and 3 trumps.
at level 3 With 15+ HCP and 3 trumps.
Jacoby 2NT with 4+ trumps & 13+ support points
Splinter 4+ trumps & 13+ support points and a singleton.
Raises or jump (simple or double) raises are not forcing. The opener may pass. Shifts are the only forcing bids : - for one round at the 1-level, - autoforcing at the 2-level, - jump shifts are game forcing.