which plugin to allow volunteers to register to fill timeslots for event

Hi All,
I’m new to wordpress and am looking for assistance in selecting the right plugin.
I’m working with a volunteer organization.
I would like to have an online sign in form for volunteers to register to cover an event for a block of time.
For example, we may have a point of distribution at a local school for a week from 10AM to 8PM for a week, and we need to man it with a minimum of three people. We found scheduling two hour shifts to work out pretty well. Although some will cover more than one shift on any one day, and be willing to work many days.

In the past we had a paper sign-up sheet with blocks of hours listed for each day that we planned on manning. Eack block had room for three volunteers to sign in.

I’d like something similar.
I’d like suggestions, perhaps something in event management, or appointment managment.

I installed “events Manager” by Marcus Sykes. It is a great piece of work, but may not be a perfect fit for my needs.