With no fit and a balanced hand responder will:
 - bid 1NT 6-9 minimum hand
 - bid  2NT 10-12 medium hand
 - bid 3NT 13-17 maximum hand and a stopper in unbid suit. With out a stopper in 4th suit bid 4th suit forcing.

With no fit but at least a 6 card suit by responder
 - bid 2 of your original suit 6-9 points
 - bid 3 of your original suit 10-12 medium hand
 - bid 4th suit forcing or with an excellent suit jump to game with13-17 maximum hand

With a fit for opener:
 - bid 2 of your partner's suit 6-9 points
 - bid 3 of your partner's suit 10-12 medium hand
 - bid game of your partner's suit 13-17

With a fit for opener:
 - in the first suit correct to the first suit with 6-9 points
 - in the 2nd suit pass with 6-9 points
 - invite with10-12 medium hand
 - bid game of your partner's suit 13-17

Opener's reverse is forcing for one round - you must bid again, even if you have a very weak response. In general, you should base your rebid on your picture of partner's hand (he's shown at least 5-4 in his suits) and try to support one of his suits if possible. Here are some simple meanings for your second bid.

• Raise of partner's second suit (1C-1S-2H-3H) = 4-card support not forcing (6-7points)
• Bid of partner's first suit (1C-1S-2H-3C) = 3+-card support (6-7points)
• Rebid of your own long suit (1C-1S-2H-2S) = very weak hand (6-7 pts.) with preferably 6 cards suit
• 2NT = weak response (6-7 pts.) with out support for partner's suit.
• 3NT = good values (8-11 pts.) with stopper in the unbid suit.
• The unbid suit (1C-1S-2H-3D) = forcing and could be artificial, usually without support for partner's suits. Like "4th Suit Forcing", a bid of the fourth suit can be used when you have a good hand (8+ pts.) and want to find out more about opener's hand.

Since the partnership is in a Game-forcing auction, with opener showing 19 (+) HCP’s and responder
showing 6 (+) HCP’s, the responder is not allowed to “pass.” Responder’s re-bid options are as follows:
 a) With Game-values, a fit for Opener, and no interest in Slam, bid Game. Remember: When in a game-going auction, a quick arrival is weaker than a slow arrival.
b)With Game values, no fit for partner, and no interest in slam, make a No-Trump response with a stopper, re-bid a 6-card suit of your own, or make a preference bid in partner’s initial opening 5-card suit, even when holding only a doubleton.
c)When Responder holds no fit for either of partner’s two suits shown, and no stopper in the 4th suit, and with no slam interest, responder can make a 4th Suit Forcing bid.
d)With a Trump fit and possible slam strength, responder can also use a 4th suit forcing bid.