To save a lab follow the steps below.
1. Click on the hamburger menu on the top right corner of the lab window
2. Click on the Save option and it will ask you whether you want to save your lab or not. It also informs you for how long (Date and Time) the save lab will be available.
3. Your lab is saved and click on Close Window.
4. The next time you wish to start the saved lab click on the Resume button. If you click on Cancel the saved lab will be deleted and you will start a new lab.