Just be careful, as there are definitely still a lot of short-comings to what occurs inside of HomeKit. My blog, as I've linked to above a few times arijaycomet.com - is going to have a HUGE article/post about this, compared to other home automation systems, in a BIG comparative view coming soon. Some of the bullet-points to be aware of with HomeKit as you attempt to make things work...
#1 - Triggers
These are controlled by iOS. Meaning if you put your phone into airplane mode, or you have no data connection (3G, LTE, or wifi), they won't occur. This is important because you can have lights turn on/off at a set time with HomeKit, where the time of day is the trigger, but your phone is the device that makes the trigger occur. One "easy" way to fix this would be to keep an older iPod Touch at home, on the wifi, plugged into power, and logged into your iCloud. That would actually work great, but its a bit of a pain. So keep in mind, your phone is the trigger point-- so if it goes down, or is turned off or whatever, during a trigger time/event, it wont work.
#2 - Local vs Away
More to that point, I have a trigger for example right now where my Hue light strip turns on/off in sync with a Lutron light in my master bedroom. When I am local this works great. Part of this is because Lutron is sending the command locally, without issue. However, since Lutron isn't using HAP over the HomeKit Cloud (yet), if I am away, the command doesn't work. So the trigger in this case isn't time-based but characteristic-based, however again, an iOS device MUST be local to see this occur. This could be resolved by Lutron using HomeKit Cloud, but they aren't at this time. So if you want characteristics to control devices, you may have to be on the local wifi with your iOS device for them to work.
#3 - Apple TV
As noted above, you'll need an Apple TV to make this work. Easy way to test this is to turn off the wifi/bluetooth on your phone, so its on 3G/LTE, and ask Siri to turn on/off a light. (make sure you're able to first already turn that light on/off with siri when on wifi first, then test without wifi second). If indeed it works, your Apple TV w/HomeKit is working. I was never able to get my Apple TV 3 working with HomeKit, but my Apple TV 4 works perfectly. So again, your results may vary, but most ATV3 owners had same complaints. Once you have ATV setup, you can control Siri remotely. This is important as I stated in my prior reply, because if you want a geofencing task to work, it may TRY to trigger that event when you're "close to home" but not yet on the wifi. In those instances, for the trigger to succeed, you'll need the Apple TV so it can "remotely" send the command. For me, geofencing never worked right until I had my Apple TV 4 setup because of this short-coming.
There are probably other important points I could get into, but that is enough to get you going for now!