You may encounter a warning from Microsoft Defender's SmartScreen when trying to install the JamKazam app.
See the image below:
1. Click the "More Info" link below the waring message.
You will now see two buttons at the bottom of the Window.
See the image below:
2. Click the "Run anyway" button to proceed with the installation.
You can proceed to sign into the app after your app launches and you reach the home screen.