How do I remove the left side cargo area panel?

2002 CRV
The owner's manual says there is a connector for trailer lights behind the left panel of the cargo area. I found the one screw under the floor mat, but lots of tugging fails to pull the panel loose.
Is there a trick to releasing the clips/panel or do I just have to be more forceful?

a little more force and maybe luck look at the air filter on that side and remove housing it will be easier uhaul .com has links on how to remove panel and screw and bolt location