Theory consits of learning the rules of polo, players’ roles and positions on the field as well as tactics. With the aid of the blackboard, the instructor can illustrate different game scenarios (back line hit-ins, throw ins, penalties, etc.) and point out the correct positioning on the field for each player. 

In the club house you can also find a wide collection of instructional videos. 

I consider it very important that whilst watching a polo match , whether on TV or for real, you must pay attention to the players positioning on the field especially in the set plays , the throw ins, penalties etc .. Most of all watch how they change strategy during the match. Being able to observe is the best way to learn.