You need to look carefully for the seam between the cover and the housing and use a blade to separate the cover from the housing. It may be hard to see but it’s there. No need to remove the whole housing from the cockpit liner like shown. I’d send a photo but I’m not at the boat.
I also don’t have the part numbers handy. Once you get the bulb out you can check for the matching pin width and voltage etc. our boat came with incandescent bulbs. I don’t recommend using them and replace with LED instead. It’s a bit difficult to match the color temperature. The original bulbs present a warm light so I’d recommend something around 3000k color temperature to be similar.