Links to Decent Rowing free training courses below. Its recommended you sign up to their email list, to get useful tips as well.  https://www.decentrowing.com/

Indoor Rowing Course

Learn the correct body sequence on a rowing machine (erg). You will get better leverage for your body which means a better rowing machine score, moving the boat faster when rowing and preventing any injuries to your body from poor technique.

Click on the picture or the link here to view the course.

Outdoor On Water Rowing Course

Now you can apply the learnings from the indoor course above and learn how to move a boat. 

Click on the picture or the link here to view the course.