Same as other internet circumvention tools, you need set up a V2Ray server outside of the firewall, then install V2Ray client on the devices that need circumvention, then you can access the Internet smoothly.
A V2Ray server can work with multiple devices in different proxy protocols simultaneously. It also can distinguish the traffic destinations between inside or outside of the firewall through configuration, it can make the traffic that direct connectable don't need to be routed though a proxy.
V2Ray also supports transfer mode, for example: As if you are inside a country which ordinary home Internet users doesn't have a high-speed international internet connection but a domestic network. There are high-speed international internet in a server room, so you can setup a server in the server room, then connect to it through domestic network.