Simple to elaborate. It all depends on your budget!
We recommend:
a computer with at least 4 gig of ram/3 usb ports
Internet connection (REQUIRED)
1 or two cameras (your choice) Cannon GL2 is an excellent camera for live streaming and easy to use.
Tripod
For each camera you will need to make the connection to the computer. You can do this by getting a small adapter (from ebay) called an Easy Cap
VMix software