Awesome that you are looking to add an additional Plaato Airlock to your app. This process is super easy and quick, here is how👇🏼
Launch your Plaato App
Power on the additional Plaato Airlock you are looking to add and make sure it is in "Setup-mode".
In your App, click on the menu button located at the top right of the screen
Click on "Add new device" and follow the Airlock set up process linked here