If you go to your fitness tracker and type "strength training" into the search box, you'll find a few generic entries (like strength training with hand weights, strength training with body weight, etc.) I would select one of those based on the equipment you're using.
I use Daily Workout Apps (ab, butt, leg, and arm) that I have downloaded onto my Nook. Each one has 3 or 4 different routines made up of 10 different exercises that you can do for 5, 7.5, or 10 minutes total. How do I add that as strength training? I don't do a specific number of reps but do what I can for the time (30,45, or 60 seconds).