Reddit reviews Car Vehicle Circuit Blade Style ATM ATT Low Profile Mini Fuse Holder Fuse Tap with 5AMP Fuse (Small Size) by HitCar

It's extremely easy to DIY. I'd strongly recommend visiting YouTube. Most customization shops will likely do it, but AFAIK it's not that common of a task due to how simple it really is to do. There's videos for pretty much any popular car model.

A screw driver, some zip ties and maybe a knife or pair of wire strippers is all you'll likely need to do it right.

In case anyone is curious here's what's involved:

1. Stick camera where you want it (likely behind rear view mirror as high as possible).
   
2. Tuck wire between headliner and roof of car, you can use a little tape if needed, in most cars it's not really needed if there's some tension. You're wiring towards normally towards the driver side A pillar in most cases since that's where the fuse box is, however in a few cars it's on the passenger side. Check your manual it will tell you. Leave a little slack for adjustments by the camera. Just a tiny bit of slack by the pillar.
   
3. When you get to the A pillar, there's normally some clips/screws that you need to remove and the plastic trim comes right off. It's made to easily come off. If your car has an curtain airbags they are here, so a little caution is needed. You can remove the neutral cable from the battery to fully disarm if you're really nervous but they aren't THAT sensitive, it's not like they inflate if you go over one of our many glorious potholes. Just don't punch the damn thing. For almost all cars there's a bunch of wires behind the airbag that go down into the dashboard. Use some zip ties and secure your new cable to those existing ones. The important thing here is to keep your new cable behind the airbag at all times, so you don't obstruct it. Just follow the existing cabling.
   
4. Tuck that cable down the hole at the bottom of the a pillar and feed it down to where the drivers. You may want/need to unclip some plastic down there by the foot well.
   
5. The ground wire can be secured to any metal part that touches the frame. There's always some screws you can remove one and use that to screw down the ground wire. Now you're half wired.
   
6. Now the positive goes into the fuse box. Since you almost certainly won't have spares, you'll need to tap something. No worries that's simple just a matter of what to tap. You can find a fuse tap for cheap on amazon or any auto parts store. Note there's different sizes. Your manual will tell you what you need or just ask at an auto parts store and they can look it up. Look in your manual for what is what, you want to tap something non-critical. Obvious reasons. It's normally a table of each fuse position and what they power. For example the radio. Something that turns off when the car is off, but works when your car is on. Pull the appropriate fuse, put the tap in, then put the fuse in the tap. Then crimp the wire from your dashcam to your tap.
   
   That's really it. All that is a detailed way of saying "thread the wire around your windshield to the fuse box then bolt the neutral to bare metal and put the positive in your fuse box tapping a non-critical fuse that's only energized when the car is on."

No splicing the factory harness... but it does require splicing into two of the wires that connect to the button. The connectors snap over two of the wires to the button (unless I can find a connector that matches the button connector).

Power comes via an add-a-fuse connector, the ground connection works on any screw / connection to the vehicle body, and the button wires are tapped via snap on T-Tap connectors.

An additional benefit is that only changes the startup state - the button still works to turn it on \ off if there's ever a situation where you wanted it on.

Tap a fuse - 1st fuse protects your vehicle, 2nd fuse slot protects your dash cam - allows you to tap into the fuse, and power your dash cam.

I have, here's my install: http://www.focusfanatics.com/forum/8943153-post48.html

My add-a-fuse: http://www.amazon.com/HitCar-Vehicle-Circuit-Profile-Holder/dp/B00U61OO50

I am assuming that the reason you want to hardwire the dashcam is because your cigarette lighter is live all the time, even when the ignition is off. If that is the only reason, you do not have to hardwire it, you can purchase a switched lighter adapter and keep the dashcam plugged in all the time and turn off the switch on the adapter when you leave the car.

I am just saying that because you have not indicated that you are interested in hardwiring because you want to use the dashcam in parking mode, and because you have said that you have no experience in car electronics.

However, if you want to go ahead with the hardwiring, I urge you to watch some videos on YouTube demonstrating how to hardwire. Here's one, e.g. https://www.youtube.com/watch?v=3I9FZL8btqc

As to the fuse to use in your car, I see that you have 3 fuses that are spare. You can use any one of those provided that it only becomes live when the car ignition is turned on. The only way you will know that is by testing it with a circuit tester.

So, along with the circuit tester you will need to buy a 'add a fuse' such as this https://www.amazon.com/HitCar-Vehicle-Circuit-Profile-Holder/dp/B00U61OO50/ref=sr_1_9?ie=UTF8&qid=1468810452&sr=8-9&keywords=Add+a+fuse

Make sure that the blades of the fuse are the same as what is in your car.

Be very careful when working in the fuse box that you don't short circuit anything. It could be bad news.

I'll show you my setup to see if it will work for you.

Dashcam - https://www.amazon.com/V1-Dashboard-Recorder-G-Sensor-Recording/dp/B00X528FNE/ref=sr_1_4?s=car&ie=UTF8&qid=1484000259&sr=1-4&keywords=dash+cam

add-a-fuse connected to an always hot fuse under the passenger side - https://www.amazon.com/HitCar-Vehicle-Circuit-Profile-Holder/dp/B00U61OO50/ref=sr_1_1?s=car&ie=UTF8&qid=1484000314&sr=1-1&keywords=add+a+fuse

12 volt to 5 volt adapter cable https://www.amazon.com/WheelWitness-Hardwire-Installation-Dashboard-Charger/dp/B00TGQ1Y3Q/ref=sr_1_3?s=car&ie=UTF8&qid=1484000362&sr=1-3&keywords=12+volt+to+5+volt+adapter

Run that to the dashcam, add a 64GB microSD and record at 720p.

You should get around 6 hours of footage before it erases the older one. You can spend a little more to get a dashcam that will support 128gb SD cards and get 12-14 hours out of it.

If you connect it to an always hot 12v fuse, you should have no problem keeping the dashcam running 24/7.

Note: In Texas, temp near the windshield can exceed 110 degrees so make you get a capacitor based dashcam if you live somewehre that gets really hot or really cold