State of Decay 2 has three possible maps that you can start your community in:
I've got two communities running on two different maps but I wanted to see the third. So I started another community but it randomly selected one of the maps I already have seen, so I decided to use the Command Center 2 power of "Research New Territories" to try to get the last one. Unfortunately, this is easier said than done. It requires 6 building materials to upgrade the Command Center to level 2. Then it takes 250 Influence to trigger the "Research New Territories" ability. And finally, you have to wait for 20 real-time minutes
Once you wait the 20 minutes, then you have 60 minutes to choose which other map you want to go to. You should load up your survivors with all the most important things you want to take to the new map before you go. Because once you get there, you'll have nothing but what you carried and some basic resources. You start at a tiny, unwalled campsite with nothing but a basic command center and a supply locker. If you don't have enough reputation to purchase the base you want ... good luck. The nights are going to be long and scary ...
It's much easier to just delete the community and start over if you don't like the map it selects for you. This is, of course, if you don't elect to start with legacy survivors.