There are 2 versions of ventrilo: the client and the server.
Client: The Ventrilo Client allows you to connect to Ventrilo Servers. You put in the connection details (Host Name/Server IP, Port Number, Password) and then hit Connect, you will be instantly connected to the server. Inside the ventrilo will be one or more channels, usually 10+ channels, all named different things. For instance, if you have a gaming ventrilo (which over 95% are for), you might see channels such as "WoW Channel", "Aion Channel", "LotRO Channel", etc. Each channel is it's own Chat room of sorts, if 2 people are in the same channel, they can hear what each other say as if they were having a phone conversation. You can have more than 2 people per channel though. During Sieges, the guild I led in Age of Conan used to regularly have 50+ people all talking to each other in a channel before we would separate into groups for coordination purposes.
Server: Someone needs to download and install the server version onto their computer and go through the lengthy setup to create a usable server that others can connect to. The public server available for download by anyone can only allow up to 10 people to connect at a time, usually runs in to quite a few problems, and should only be used by people who know what they are doing. Fortunately, there are certain Ventrilo Server Host companies, who will set up and host the official version of the server (which can hold anywhere between 10 and 150 people depending on the version you request to be hosted) online, requiring no setup on your end other than the optional task of naming channels and registering names. The company then allows you to create a Master password, and gives you the connection details for the vent server. You connect to the vent as a Guest account using the client, put in the master password to make your guest account have Administrative privileges, and then have the choice of creating channels/user accounts/changing password etc. You can then give the connection details to others, allowing them to log on as guests if you don't want to create accounts for them.
