As you see in the picture I am looking at the room modeled through the camera perspective:
I want to change my camera settings to be able to render a picture of the whole room. How can I do that?
This is the Default 35mm frame
There are two ways you can bring more content into frame.
Back the camera up (I prefer fly mode over grabbing because I can see the result while doing so)
Go into fly mode,
shift + f,
do not move the mouse while doing this (otherwise you will change what you are looking at)
Note that cameras with a low focal length can look weird, look at this
Focal lengths are good, but what I find useful for many of my projects is opening the menu by pressing "n", go into camera view by pressing 0, and then enabling the "Lock camera to view" option. This will allow you to change the camera angle just as easily as you normally can in the viewport.