In games with blinds, this amount is usually the amount of the big blind. Modern poker rules require that raises must be at least equal to the amount of the previous bet or raise. For example, if an opponent betsR$5, a player must raise by at least anotherR$5, and they may not raise by onlyR$2.
Check, in poker terminology, simply means to refrain from betting when it's your turn to act. But you can't always check. If another player bet out before action came around to you, you must either call, fold, or raise. Pass  is a synonym for check.