Rhythm Tap is a specific style of tap dancing that emphasizes clean rhythms, loose ankles and close to the floor footwork. It has little or no emphasis on upper body movement/ stylistic postures, choosing instead to focus on the complexity of rhythm, tempo divisions and tonality/musicality of the taps.
Fred Astaire/Gene Kelly are not examples of rhythm tap dancers, although they were very famous tap dancers. Look for Gregory Hines or Derrick Grant on Youtube instead, to have an idea of what rhythm tap is like.
 
In absolute beginners we will learn all the necessary beginners steps like shuffles, flaps, ball changes, learn how to perform them with a loose ankle, learn to keep time with music and also move between tempo divisions. We will do exercises both without music - and with music. In keeping with roots of tap, jazz music from the 30s and 40s will be the main genre of music used.