
Apologies for how minging my windows are, it's winter here in Iceland, and a ten minute drive to work makes your car look like it's been pelted with shite by a troop of monkeys

There's no need to remove or loosen any trims, everything fits without needing to unclip anything, given the slimness off the constant power cable for the Garmin mini 2 and the fact the OBDII port isn't covered with a plastic trim.
First choose a location for the camera and get it set up, I put mine right in the center of the windshield at the bottom of the camera/rear view mirror array.
You might want to choose different, up to you, The camera is so small that you can get away with this position, and it's nice and close to the glass so there's no reflections.
The camera is also easily accessible to adjust the angle and remove the SD card if you need to.
You can then feed the cable up the side of the camera cover by pushing it in the direction that the arrows run, to hide it behind the trim. There's enough space to push it here.
I've pulled my cable out a bit here to show you how slim the cable is, and that it will fit.
Next take it up around this corner, I've pulled mine out a bit again so you can see it, just ease the cable in behind the trim, it'll go without very much pressure at all.
Continue to feed the cable, pushing in the direction of the arrows all the way along the top of the windshield, pushing it up behind the roof liner, until you get to the a-pillar.
When you reach the a-pillar, a little more pressure is needed to guide the cable around the edge of the plastic trim, between it and the headliner, and push it downwards behind it.
Do this all the way around to the door seal.
At this point, you don't need to remove the door seal, there's a large flat flap on the inside of it that just lays over the beige plastic trim, you can lift it with something like a butter knife, just gently.
You'll be able to see the gap between the plastic trim and the frame of the car, feed the cable in there, all the way down to the bottom of the dashboard.
You can see the gap behind the seal next to my fingers, in the seventh image below, this runs all the way up the a-pillar of the car.
To feed the cable behind the seal, just get it started then push it in behind the black rubber in the direction the arrows show in the picture above. It will slip into the gap freely.
When you get to the bottom of the dashboard, there's a handy little gap between the dashboard and the trim that the hood release latch is in, you can just feed the cable in there.
You can also see the gap I was talking about between the frame of the car and the a-pillar/dashboard trims.
Next, run your finger all the way up the flat part of the seal to make sure it's properly seated against the beige a-pillar trim.
The OBDII port is right by the plastic trim that the hood release latch is in.
You can plug the constant power plug into the port, plug the USB cable into the socket on the plug's cord, and tuck the rest of the cable behind the trim that the hood release latch is in.
Mine is pulled out a bit here so you can see the cable behind the trim.
The constant power cable has three positions on the switch, 10m, 24h and an infinity loop.
You can set how long the cable provides constant power to the camera before it shuts off once you turn the car off.
I have mine set on the infinity loop, as the cable monitors the voltage of the 12v supply, as it has 12v battery protection built in.
This means that it'll always provide power and keep the camera in standby, so if it detects and impact or incident, Parking Guard will start recording for a couple of minutes.
I've been using mine this way since I bought the car in May, and it's been great.
Hope this helps with your install!