Select the Varase or Geetham from the picker, see the lyric, and hear the rendition. You can pause and resume playback. Use the next and previous arrows to go the next lyric in the same song or go to the previous lyric.
See support page (https://cgavini.github.io/chinmoy/carnaticmusicsupport.html) under "Legend" for a description of the notation and color coding used.