Open the app once you have downloaded the Houseparty and see the home screen. It is a video feed of your face with various symbols outside. By clicking the plus sign (+), you can start the conversation or group call in the app.
Select one or more of your friends (they must first add to the application) and press "Invite to the room." You are now online, and you can chat whenever you want. You can also use the + menu to add new friends or invite people without an app to download them.