How do you make more than 1 family on the sims 3?

You go down to the three dots (Orange Circle) and click on it and search for the option "Edit town" and you enter into your town and shows a few options to edit the town etc. You go to create a a househould (Red Circle) and there you can create a family. After you created the family, you land here again and at the bar next to the Red Circle, the family you made will appear there.

Hope this helped

while you are playing with your families press the (...) and click edit town and make a new family and move them in but you'll still be with the family you started with and you can change to that family if you want or play as your family with that other family in town doing stuff any other sims would

When you start playing Sims 3 and you have to select the houshold you want to play, select new game. That way you can have as many controlled households as you want. But the pre-made characters stay the same but live different lives in each game so it can get wierd...