I have a Concept II "erg" in the basement. That machine will strengthen you up, tone you up, but not bulk you up. Much like cycling or swimming. And start S-L-O-W. recommended first 3 sessions are 12 minutes or less. a lot of small muscles and tendons get engaged that are not typical for most people and an aggressive start almost guarantees an injury. over time, you get good form and the right mindset, and then that simple looking machine can give you as much workout as you can take. lots of useful edu material here:
Best-selling Rowing Machine -SkiErg -Exercise Bike | United States