This convention is applied by the Opener after the simple support of the openning major. In order to apply this convention, 8-9 points of responder should be sufficient for the game.
Game Try could be applied in two ways; the first is to increase the major to the third level, the other is to search help in an other suit. If the opener does not need any help in any other suit, then increases the level and invite the responder to game. Responder will pass with the minimum points, but declares game with 8-9 HCPs.
But if the opener needs help in any other suit, then declares that suit. This shifting suit does not mean a slam invitation, because in case of simple support there is no slam possibility. Responder will return to the openning major in third level with the minimum points. Otherwise responder may declare game with stopper at the second suit, or may bid another suit having some value. In this situation opener conclude the last decision.