Adding Core DBs

I am a bit confused on how to bring in my core DBs. I have 16. Each one is a wide open “select all” for argument sake. From there these DBs will get pulled into various pages with conditions. One page might hit the core employee DB and just list active employees, another page might hit the core employee DB and list people on call this week.

I’ve used a different DB tool which was similar and this my mind id set on how I used to do it and I’m struggling.

I guess I’m not 100% understanding the whole Core DB > Project > Template sequence.

Thanks