Remove panels to access tail light wiring

Hi. First time using this. My driver side brake light doesn’t work. First I bought a whole new assembly and installed and still doesn’t work. After looking in the little access port I see that the blue wire is broken. I have non idea how that happened but I need to access it so I can strip the wire and reinsert it. I can’t adequately access it without removing interior plastic side panel in the cargo
Storage area. Anyone know how to remove the panel. I did get one screw out but it’s attached to the upholstery.