The Virginia Department of Elections has prepared a guide for officers of election to use on election day. It's organized as a reference to problems you might encounter (What Ifs) and how to deal with them.
Many localities use the guide as prepared, some adapt it to their own circumstances, so you may see officers of election with a guide that looks different, but it will offer the same guidance for resolving problems.
Download a copy and review it. Take it with you on election day if you're serving as a poll watcher.
(Last Updated 11/2022)