Trunk lid replacement?

I have purchased a new trunk because my old one has a dent. The arms of the trunk reach into the trunk, and they are mounted to the inside roof of the trunk. To get to the 4 nuts secured on the other side it seems like I need to remove the rear parcel shelf. The shelf is secured with my little pins that can be pushed out which I squeezed all out. However, I am having trouble removing the parcel shelf. It seems to still be stuck and I don’t want to break it. Is there a trick to get to those 4 nuts without removing the shelf? Or how can I remove it? I attached screenshots of how the parcel shelf looks like.