Manage student usage and streamline student access to sites you want to share with Vision. You can see screens of all students, ask for attention (sending a prompt that takes over all screens until you dismiss it), push a link to everyone, or share a lesson from your own computer screen, among other abilities.
The district has a license that covers students, so you should be able to access it for free throughout the year. To use Vision from your school Mac, go into the Chrome browser and download the Vision Teacher app.
You don't need to enroll students on a one-time basis to use Vision. Instead, everything runs through Google Classroom.
Have students log in to your Classroom, then start a Vision session. Students will receive a prompt to "Share screen" and join the session. From there you can access the various features. At the end of the session, close Classroom and you're done.