In the AppStream navigation bar, on the right, click the User icon, then select End session.

Disconnected sessions (closing the web browser) and idle sessions (no keyboard / mouse activity) will stay active for 60 minutes and then be automatically logged off. If you fail to reconnect or actively use your session before the 60-minute timeout ends, all your unsaved work will be lost and you will need to start over.

Be sure to save your work often.

If you are using OneDrive, always copy your work from temporary storage to OneDrive before leaving your computer or doing other things on your computer. If you are using Google Drive for file storage, you do not need to copy your files anywhere.