There are many things to do before you ever recruit the first volunteer. The resources here discuss the many things that are needed to prepare your organization.
Produced by the National Centre for Volunteering (UK), this booklet examines how developing the right policies leads to a more diverse volunteer corps.
Created as a "A Guide for South Australian Local Government" by the City of Salisbury in SA, this contains many useful tips for determining potential risks in volunteer work, even if the legal issues discussed will not be the same in all locations. Also suggests ways to create volunteer position descriptions from a health and safety perspective.
Major source of information and publications on all aspects of risk and liability for nonprofit organizations in the U.S. (much is relevant in other countries, too). Volunteer risk management is one of their featured areas: https://www.nonprofitrisk.org/areas-of-expertise/volunteer-management/.
Demystifies risk management and sets out in plain language what every volunteer program needs to know about this sometimes scary, always critical subject.
Outlines the key executive decisions necessary to lay the foundation for successful volunteer involvement: policies, budgeting, staffing, employee-volunteer relationships, legal issues, cost and value of volunteers, and more.