volunteer opportunity at YNHH

Hi everyone! I'm hoping to volunteer at YNHH and saw that the applications form requires 2 references. For anyone who has applied before, do they actually reach out to the references you listed? If so, did your references have to submit a full recommendation letter or is it just some sort of simple form to fill out?

Also do they accept volunteers year-round or only in batches at specific times of the year? Would also love some suggestions on other volunteer opportunities!