You will need the Full Write Service Plans permission to change sign up settings on a service plan.
A login is needed for the church congregation to sign up for specific serving opportunities.
Serving needs on a service plan can be published for others to browse and sign up for. This is controlled under the Settings > Signing Up tab of a specific plan. Each scheduled team is listed along with settings controlling how they can be scheduled.
If a team doesn't appear in the list, it's because they aren't scheduled on the plan yet. Each position can have one of the following sign up settings:
Only admins can schedule volunteers - this is the default setting. Only group admins and users with the Full Write Service Plans permission will be able to schedule volunteers to serve on this plan.
Only current volunteers on roster can sign up - this allows volunteers currently serving on the team to sign themselves up for an open spot on a service plan.
Anyone can sign up to serve - anyone in the system can view and sign themselves up to serve for this position on the plan.
If option 2 or 3 above is chosen for a position, that need will appear under Serving > Opportunities tab in the left-hand menu. A login is required to access this page.
They can also access this screen by clicking on the "Browse" button within the "Upcoming Serving" widget on the home page dashboard after logging in.
From here, users can sign up for an open spot to serve by clicking on the "Sign Up" button. Once signed up, they are assigned to that position on the appropriate service plan and their status is changed to Accepted.