AltspaceVR is a virtual reality platform for hosting live events with up to 70 users. It allows for a variety of private and ticketed events like meetings, conferences, classes, and social gatherings. Users can create customized private events and control features like restricting stage access, moderating Q&A sessions, and using emoji reactions. The guide provides an overview of AltspaceVR's capabilities and instructions for downloading, setting up an account, navigating controls, and completing the tutorial.