To install and connect the Insert Viewer demo app to your account:
Go to 'My Apps' tab, on the relevant Insert Viewer app (iOS/Android) - click on "Install and get PIN Code" link. You will find there the links to the app in the app store / marketplace.
You can also simply look up "Insert Viewer" in the app store or marketplace.
Once you've downloaded the app, enter the PIN code that is provided under "Install and get PIN Code".