Volunteering Scotland has an amazing list of resources to help you manage and support volunteers. It includes templates and guides to creating volunteer induction packs, role descriptions, policies, measuring impact and creating an inclusive environment. All these resources can be downloaded here:
https://www.volunteerscotland.net/for-organisations/guidance/all-guidance-and-templates/
Heritage volunteering group is another good site for resources and support – https://heritagevolunteeringgroup.org.uk/links-resources/