Please follow the instructions in the included Quick Start Guide: https://www.elgato.com/sites/default/files/Eve-Door-Window-Quickstartguide.pdf
Eve Door & Window
With Eve Door & Window, Eve understands whether your door or window is open or closed. See the current open/closed state at a glance and view statistics on time & duration to make smarter choices.
1) Download the Elgato Eve app from the App Store.
2) Insert the included 1/2 AA (ER14250 3.6V) battery and place Eve Door & Window so that the areas marked with dots are facing each other. You can use the included elements to bring the small element to the ideal height.
The built-in LED will light up each time Eve Door & Window detects an open/closed state change, so you can be sure everything works as expected before attaching the adhesive firmly.
If you want to replace the 1/2 AA (ER14250 3.6V) battery, simply pull the larger element downwards - no need to remove and re-attach the carefully positioned adhesive.
3) Open the Elgato Eve app and tap Add Accessory. Eve will now guide you through the setup process.
If you have already set up another accessory, go to the Eve settings to add Eve Door & Window to your home.
HomeKit Setup Code
Please keep your HomeKit Setup Code in a safe place. You need it to securely add Eve to your home, and nobody but you has a copy.