Getting a blank (black) screen when joining a campaign, and no music...

Are you trying to run Roll20 directly in Chrome or are you trying to run it as an app within Google Hangouts?

Here's a checklist of methods that'll hopefully help your predicament, Lindsey. When the players are introduced to any given map, their view is always aligned to the upper left hand corner of the screen. If your GM has Fog of War enabled on that map and hasn't made the upper left portion of the map visible, all you'll see as a player is black space when your map loads. Your GM can force your camera to move to a desired spot on the map by Pinging the map while holding the shift key. Double check with your GM that he/she is actually remembering to reveal the map if Fog of War is enabled. Regarding audio, double check your volume settings. Click on the gear tab for My Settings. Make sure the Master Music Volume slider hasn't turned all the way to the left (and essentially muted your feed). Also make sure that you have "Video and Voice" or "Voice only" selected under the "I Want to Receive from Others" field that's towards the bottom of the My Settings tab. Other things you can try: Whenever you start up Roll20, you often have to play around with the audio feeds of yourself and others in the game. On the bottom of the battle are names and avatar pictures of people currently in the game. If you mouse over the bottom of an avatar's picture, it'll display a volume slider. I tend to have to max out everyone's volume to hear people and they in turn need to max out their own audio. If people are having trouble hearing you, go to your own portrait and bump up your own volume slider. Were other players able to hear the music? If not, double check with the GM that he/she's is playing their music from entries added to their jukebox tab. If they're playing music from the "Add Sound" soundcloud search dialog box, they're only previewing the music on their end and it doesn't get transmitted to the players. I hope the above helps. Let us know if not.