Rowing is one of my favorite exercises especially when my time is limited. Rowing works the entire body, hitting muscles in the core, legs, arms, back, and butt. Not to mention it is a smooth workout, which is always a good thing. (especially if you are prone to back and knee issues)
Try this 30-minute interval workout you will get in your cardiovascular activity while simultaneously engaging many major muscle groups for effective strength building.
RPE (Rate of perceived exertion) is a scale used to measure the intensity of your exercise, 1 being easy and 10 being all out. The rowing machine will show you SPM (strokes per minute) for the harder intervals aim from 26-30 SPM and lighten up on the easier intervals. Good luck!