You mentioned that you wanted to get as much of the hotel in as possible. Shooting it as you did, you ended up not getting much of it at all, in the sense that what is showing is too dark to see. (On my monitor anyway.) Shutter speed affects the amount of ambient light in the screen when shooting flash, while aperture affects flash. What I would have done is taken both the camera and flash into manual mode, and exposed first for the background, and then adjusted the strength of the flash (1/4 power, 1/2 power, whatever) until you got a pleasing result on the people. Had you been shooting earlier in the day when there was more ambient light available to "light up" the hotel, it would have been much easier. But when you are trying to balance low light and flash without the background going too dark, you have to understand how your flash works in those situations. Read up about "dragging the shutter", you might find that helpful as well. I'm not sure where you are in your photography journey, but what you were trying to do in shooting people and a background like that in low light is difficult if you don't know all the ways to get around the problems. (lighting the background separately, for example, or shooting manual as I described.) Maybe you can bring up the background in photoshop? Still, the fact that you have all the family together in one shot makes it special, technicalities aside!