Volunteers give their time by choice. What motivates them? Why do they want to get involved? Find out. Ask them. See Recruitment (Induction Interviews)

"Why did you choose to volunteer with us?"
"How would you like to be involved?"
"What do you hope to get out of volunteering with us?"
"What do you need from the organisation?"

Understanding what volunteers need and why they joined can help you to meet those needs and motivations when operating the program. Meeting the needs of volunteers can help them stay motivated and feel that their contribution is valued and worthwhile.