Finding new volunteers while you are looking for applicants can be daunting. It's a chicken and egg challenge - how can you get applicants without teams? If you wait till you have full teams, they won't have anything to do with no applicants.
So, you source applicants while sourcing students. At least with volunteers, can you continue to source them after the class starts (and you need to!)
Like the applicant process, it's a funnel. For example, some volunteers will sign up for a recruitment event, but not attend. So your goal is around 250 signups for 25 active volunteers.
How to proceed
Make a list of organisations to contact, prioritise and start contacting them