Assigning Devices to Students in Classroom

The devices are greyed out, and we are hoping to assign a specific device to a specific kid for each class. It says there are 13 devices (correct) but also that there are none available. We use Mosyle and they all show as "Shared" in there.

Anyone have any idea where to start so we can utilize the assign devices option? Note, working through the Mosyle class app, you're allowed to assign devices "auto" and it doesn't seem to necessarily give a student the same one each day. The other option is present them with a list of students on screen to choose from.

Ultimately, we just want Student A to use Device 1 each day, and when a class starts he'll be auto logged in or just press Start. We have a different group of kids in several classes using the same devices.