If you do not need or want parking mode then it is a simple matter of wiring into the fuse box, with an additional small inline fuse for the camera.
The car will most likely have a few main fuses, then a secondary fuse for this main sub circuit, then you add a third fuse of 1 to 2 amps for the camera. Off the shelf generic parts is all that is needed.
If you are using parking mode it is better to use an auxiliary battery and a DC-DC charger with the Garmin parking adaptor. You should avoid using the starter battery for parking mode, starter batteries are undersize and overworked on cars these days.
You could also add a solar charger to keep the auxiliary battery charged.
At the bottom of the photo are two DC-DC 9amp chargers (which can be connected in parallel as many as you like. These are older non smart chargers), just above is a MPPT solar charger (with custom heatsinks, for my own reasons) with Bluetooth data to your phone with 30 day history.
If you want parking mode shove a battery (I have four 26Ah) in the car somewhere and DC-DC charger, preferably a more recent smart charger. It's not that difficult and you have a great auxiliary battery setup to run whatever you like, within reason!
