Installing is pretty simple. Head to the iPhone app store (or google Play if you have an Android) and download the Immich app. It should be the one with this icon next to it.
When you run it for the 1st time, you will need to login with your email address and the password I provided you with. If you forgot your password, call me and I’ll reset it.
That should be all. It should start backing up your photos automatically.
Keep in mind if you turn off your iPhone, the Immich app will be terminated and you’ll need to start it again, but it should keep running in the background so that when you take a photo (or video), the next time you’re connected to WiFi it will start backing up the new photos.