You access the settings menu from the settings icon in the top right corner from any screen.
From here, you have access to settings for your Account, and files on your device.
Under your account, you can see the username that you are logged in with and the version of the app.
You have the option to activate a pin code for extra security and to logout of the app. If you have a pincode activated, you can deactivate or change it.
Press the same setting icon in the top right corner to exit the setting menu.