If you go to Recruit in the navigation, you will notice there are two tabs: Assignments and Event Roles. Timecounts has two ways you can schedule and organize volunteers. There are a few subtle differences to know.
Event Roles are used only when scheduling Events.
You can create a Role from within an Event using the Role button in the toolbar of a schedule, or directly from the Event Roles list view under Recruit. When you create a Role, it also becomes a template that you can use in future Events. This allows you to also save a description and related skills for the Event Role. Not only does this save time, but it allows for easy reporting to track Roles across multiple Events.
While you can always find out who previously volunteered at a particular Event, volunteers are not associated with that Role beyond the Event. This means they need to sign up and/or apply for the relevant shift again in future.
Assignments can be used with Schedules or on their own as a standalone application.
The two main differences with Assignments vs Event Roles:
Assignments are decoupled from a Schedule, which means people can complete an application without having to pick shifts right away.
Assignments have a volunteer pool of qualified people, which is linked to permissions that let them view a schedule. This means they will not see any shifts they are not already qualified for. It also means they don't need to continue to apply again and again, they will be updated when a new schedule is out to come and pick their shifts.