@vongomben
As @Steve-Mcl Steve says use projects. Then you can create a project and call it something like 'Start-up-flow'. Fill that in with what you need to start the class. Then export the flow as a backup.
Now when you start a class you would:
open the 'Start-up-flow' project
export the entire flow using the 'Copy to Clipboard' button
create a new project with the class ID as the name
from the hamburger menu (top right on the screen) select import
paste in the flow and deploy it.
Now you have a clean flow to start with. When when the class is over you can just delete that classe's project or keep it for future reference.