When you are finished with a training session, you don't really need to log out of the site. It is perfectly safe to stay logged into the site after you exit.
The site will automatically keep you logged in for 24 hours and then log you out if there is no activity.
If you just want to log out after your session, you can do this by going back to your Members Portal here.
Then click the 'log out' link in the bottom footer of the page.