... on the same network(or just select the NAT option in your virtualization software). It is suggested that you use the NAT option along with port forwarding, but as long as you have TCP access to the VM, you should be fine.
There are no supplied credentials, and it is intended that the network services on the VM are the attack vectors.
If you have questions, feel free to ask in #vulnhub on freenode(I'm bwall on there). You can also ask me on Twitter(@botnet_hunter).