For me, it started with the Nest Protects (Smoke and CO detectors), then a Nest Thermostat, then more Protects, now some cameras, and some other products: A WeMo (Belkin) smart outlet plug, and now a Philips Hue bridge and two lights. It’s a slippery slope. A gateway drug. But it’s also a huge technical PITA. Today, I spent hours installing two light bulbs and configuring them properly.

Things I’ve learned:

• If you want to use some catch-all controller like Apple’s Home app (aka Homekit), all of your devices have to be able to connect to something (of the same brand), called a bridge. And the bridge has to have a “Works with Apple Homekit” or equivalent label and code.
  
• Some of Apple’s Homekit is still super weird and hard to figure out even with the help of 2 Apple Geniuses.
• Apple’s Homekit in particular refuses to work in some cases and devices (like the AppleTV) without something to control. The Home app, working as a hub on an iPad, also, can be super finicky about order of setup. Part of the reason I spent hours is I didn’t understand not to set up the Philips Bridge and lights until after Apple/iOS/Siri got ahold of and integrated with them.
  • So to make it clear, the order of operations I had to do was:
    1. Install the Home app and the Phillips Hue app on the iPad, but don’t do anything with either yet.
    2. Plug in and connect the Phillips Hue Bridge
    3. Screw in and make sure there’s power to the light bulbs
    4. Start the Apple Home Hub on the iPad through Settings -> Accounts -> iCloud.
    5. Start the Apple Home app on the iPad.
    6. Add the accessory (the bridge) to the Home app.
    7. Wait until the Home app told me to open the Phillips Hue app on the iPad.
    8. Open the Phillips Hue app and do the things I was prompted to (look for exclamation point alerts and follow prompts – if there’s an update, let it roll. Set a timer for an hour and check back then. There may be more than one update, and they may take a long time.
    9. Two times during this process, the bridge or the Apple Home app seemed to lose its mind. The key here is to wait as long as you can bear it and see if it fixes itself. If you give up waiting, you probably have to reset the bridge with a paperclip and reconnect it to the Home Hub app on the iPad. And again, follow any prompts that tell you to open the Phillips Hue app, and follow those prompts.
    10. Eventually, the updates finish with the Hue app, and things start to work normally.
• Set up rooms, device names, automations and so on with the Home app. You can do this with other Home apps on other devices as long as everything’s using the same Apple ID, has iCloud connected, and is on the same network.
• After all this is set up and working, you can enable Home hub on something like, e.g. a 4th generation (and apparently some 3rd generation?) Apple TVs. Or on an iPhone with the same iCloud account and the Home app running.
• If you have an AppleTV, for instance, with a Siri-enabled remote, you can hold the Siri button down, tell it to “turn on the front porch light” and it’ll happen.
• Nest, notably, doesn’t work well with HomeKit. There is a Node.js server based solution called “Homebridge” that you can hack together that’ll do it, but that’s pretty advanced.

I’ll update more as I have more experience(s).