Here is a link to the thread where I've linked the app code and driver code. It's an age since I first installed this it but I'll try and also locate/link the original post that has more details of installation:
From memory, you:
- install the app code - Apps Code > New App > paste the code > enable oath > click save
- install the driver code - Drivers Code > New driver > paste the code and save
- install the app - Apps > Add User App > Select 'Evohome (Connect)' and install it
- enter your username and password that you use in the Honeywell app
- go to your device list and the thermostats should be there
Mine is the zoned version of the system working off individual valves. When you log into your account in the Evohome (Connect) app it creates child devices for each zone using the driver that was added. As yours is a single thermostat I assume it just might create a single device.
Edit: There's further information in the thread linked below starting at post #19:
