The redoble (meaning roll) is a great step to have in your repertoire. It is a group of 5 or 6 sounds (or beats) that are performed quickly over 2 beats (or counts) in the compás.
The redoble is used many times as an accent in phrases of footwork and often in Llamadas (calls). When you are practicing try not to hammer your feet into the floor so all the beats have the same volume. The step should sound like a roll with the last golpe (stamp) being the loudest sound.