Switching between two tracks on playback

EASY..... open the program.... move the two tracks SIDE BY SIDE so this is easier.

NOW.... click ONE of the SOLO buttons...it turns green  place your pointer on it ( the solo button) and RIGHT CLICK. select GROUP and choose one of the colors at random.

NEXT ...choose the other solo button but do not click it.... instead, Right click it and choose the SAME color GROUP.... select it.

Now, when you click either solo button the tracks will switch.....

If you are doing that in a mix to see which track works best.... use the MUTE button instead and group them the same way described above..... if you choose solo, you'll only hear the soloed tracks..... mute will let you hear the background tracks and only the unmuted one....