Well, first off, you should never import media from a camera card.
Transfer the files onto your computer first.
File-import
that is how you import an audio file.
Is it with a video clip?
Open your media browser, bring in the footage, drop it all into a sequence, unlink and delete the video track. Or double click a movie file in the project and you can drag the audio only over to the sequence by grabbing the audio symbol.
Chris