Lots is being made of the MANUAL mode, and that is fine, It is very useful for learning the fundamentals of this magical pastime.
I used it for 35 or more years, because they didn't have all these marvelous choices on the Graflex 4 X 5 or the Leica M-4, or my Pentaxes, or anything else back then. I still can shoot MANUAL, but WHY? Except for severe backlighting, and a couple of other situations.
That's why I LOVE the features of my digital camera.

That's why we paid all that money for our cameras, right? So IT could sweat most of the hard stuff!
Use the features.
Everybody does, but the Manual shooters just won't admit their cameras are better at some things than they ever can be.
For parties of any age people, and/or those not really familiar with their shooting equipment, it is best to try each option before the event, writing down what works, and what doesn't please you.
Pre set everything you can , so you can concentrate on the activity, and not be messing with settings every 90 seconds.
If your camera has them, try the pre-programmed modes,which live on the dial with the PSAM selections, usually marked by clever icons, which the camera manual wil help decipher.. "Party" mode or its equivalent, or "KIDS" are good ones. Nothing wrong with AUTO, either.
Now, go take some pictures;

the more we shoot, the better we get!