I also use the Bowflex and have been getting the 20 Minute Better Body Workout done for awhile now. According to my Owner's Manual and Fitness Guide, the frequency of this program is 3 Days Per Week.

"Start by performing one set of each exercise. Warm up with a light resistance that you can perform easily for 5-10 reps without fatiguing. Focus on practicing and learning your technique before increasing the resistance. Then move to a more challenging resistance that you can perform no less than 10 reps and no more than 15 reps without your form deteriorating. As you become stronger, you can advance to two sets for each exercise. Complete all sets of each exercise before moving on to the next one. Rest 30 to 45 seconds between sets. Move slowly on each rep. Use a pace that would allow you to stop the movement instantly at any point in the rep. Count three seconds up and three seconds down and work to fatigue during each set."

I hope this helps!