When you say hardwired, do you mean hardwired into that little black box or hardwired as in the fuse taps are integrated? It's effectively the same setup as using bullet connectors, although personally I like to use my own fuse taps (add-a-circuits).
The red and yellow wires will be individually assigned. One goes to an ACC+ fuse slot (only receives power when the ignition is on) and the other will need a BAT+ fuse slot that receives constant power, whether the ignition is on or off. The instructions will say which colour goes to what. Usually the ACC one is just a signal wire so it knows when the car is on or off and the power always comes from the BAT+. Connect the ground to a suitable bolt and then plug the USB-C cable into your camera and you should be good to go.
However, if the black box is just a voltage convertor and not a battery protect and your camera doesn't have anything built in to limit voltage drain or parking mode duration, then I would highly recommend getting a battery protect device instead.
This is the hardwiring kit I fitted last weekend:
https://viofouk.co.uk/product/type-c-hk4-hardwire-kit-cable-for-t130-dash-camera/
I used my own fuse taps and I also use ferrules on the red and yellow wires for a tight fit when crimping the fuse taps. (
link)