All you need to complete the challenge is a pair of dumbbells; Millis suggests starting with five-pounders, though you can increase the weight or use different weights for different exercises, so you feel appropriately challenged. It’s clutch not to race through these moves; instead take your time to feel your muscles work — both on the exertion (the pushing or pulling action) and on the release. On days when you’re doing more than one set (noted by “x2” or “x3”), take a one-minute break before starting the next one. And on days that have more than one exercise, do them back-to-back with minimal rest, only taking that one-minute break between sets if there are more than one. The schedule also includes all-important rest days , which is the downtime your muscles need to repair from the work you’ve done, so they can become stronger than ever.