I have a DS but, I strongly suspect that panel is your access. Otherwise, why the finger hole? If you look closely, you should find one, maybe two wood screws in the forward area (not crawling under the bed). One out, attempt to pull up at finger hole. Newmar puts those panels in tight so be forewarned.
2019 DS 4018 (Spartan), Nighthawk
2015 Jeep Wrangler Sahara