Been on this journey that you are starting on.
Your final goal should be Manual settings, with playing with av etc. along the way.
Simple to remember, after lots of practice: Shutter Speed controls ambient light and Aperture controls flash.
Sounds simple but sometimes difficult to get ones head around it.
I shoot a number of community events, some weddings and some engagements, Kids, adults, some posing, most not.
Settings when i shoot generally are manual : F5.6 (reasonable depth of field) and 160th (freeze motion for the ambient lit stuff). Then set the flash (580ex2) for ETTL. Point flash to ceiling or wall, have reflector card pulled out (so i get highlight in the eyes). people love my pics, the focused ones of course. so i must be doing something right.
If it's a group, and i have not prepared with multiple lights, i increase the f stop, to give greater depth of field, slower shutter speed, say 100th, and let the flash work harder, still on ettl.
Next goal for you then is to have everything on manual, including you flash. But the above works REALLY well for me.
For more stuff look for Joe Mcnally, Zack Arias, creativelive.com.
LOTS of free stuff, that's how i learnt.