You can’t use the onboard mic of an iPad on which the AeroCaster LIVE app is installed for audio input. Instead, use the MIC connectors on the VRC-01 to input your audio.
You can output the audio from audio or video files that were imported into the AeroCaster LIVE app. For details on importing files, refer to “Assigning Audio, Still Images and Video on an iPad (MEDIA)” in the “AeroCaster LIVE Owner’s Manual”.