lift gate inside panel

I just bought a used 2012 Mazda5 touring last month, unfortunately the 2012 touring didnt have even the parking sensors. So I wanted to install a back up camera for it . This's my first car job ever to do on my own so I was bit nervous about removing the whole panel of the lift gate...

Some rude person backed into my 08 CX-9 and broke the trim piece over the back license plate (I'm told it is called the lift gate garnish). As a result, it is loose on the right side, which houses the keyless entry button and one of the license plate lights. I would like to see if it can be...