Feel free to do anything which gets your heart rate up during the cardio breaks.
Some recommendations are: jog, run, run on the spot, skip, and even dance. You can also choose: fast feet, high knees, skaters (slow or fast), shove offs on the wall, anything that increases your heart rate.
To find the video and description of any exercise:
1. Go to 'Profile'
2. Tap on the 'Exercise library'
3. Type in the name of the exercise you’re looking for, or browse through the list