This is a common issue that is easy to fix.
Turn your iPad screen side down on a clean surface so you see the apple symbol on the back. On the left side, you'll see two buttons, the volume control, and a small, round switch. This switch can be set to control the mute function of your iPad or the screen orientation. If you're having trouble hearing audio, it's likely that it's set to control the mute function. To unmute your TouchCast, push this switch up to the off position, as seen in the image.
Also, make sure no headphones or recording devices are plugged into the iPad.