To login to Testnetic go to app.testnetic.com and enter your username and password. Should you be unable to recall your password your may reset it. An email is sent to the registered email address where you can subsequently change the password..
To logout your may simply close that browser window and you will be exited from the application, however your login credentials will be remembered. The next time to login your will have to provide the correct email address and password to successfully login. Naturally whilst convenient it is not the best security practice. Should you wish to ensure next time you login to Testnetic should should logout via the menu item Logout as shown in the image below.