An "aerobics session" refers to a type of exercise class or workout that involves rhythmic movements and physical activities to increase heart rate and improve cardiovascular fitness. Full definition
For example during the first week you can add two aerobic sessions not longer than 10 - 15 minutes. (fitnessandpower.com)
B) engaging in moderate amounts of low volume movements throughout the day, including walking, standing workstations, gardening, and easy, aerobic sessions fueled by high amounts of fat intake from coconut or MCT oil, nut butters, etc.. (bengreenfieldfitness.com)