There are many great videos from people like Dr. Tim on youtube. For a student leadership training, there are also handbooks that are designed for the teacher you could use to create a "curriculum". Those books are for sale at places like amazon.com or bookstores I am sure.

Think about your own goals and purpose for why you're doing the training.

Are you trying to improve the culture? Are you trying to help them learn how to be marching techs? Your leaders shape your band program so they are worthwhile to invest in.