Using My Own Wifi

Ok. I'm a noob at this. I was just wondering. Could I use my own wifi to capture passwords and do various other things to people that hook up to it?

If so what kind of things can I do? And don't yell at me for this I know it's not the type of question that is well received on these boards.

P.s. I've installed Kali, I bought a book on pen testing wifi with Kali, and I have raspberry pi3 on order to help learn programming. So I marrying here people.