If u have a sound card, u can record audio very simply. if u are recording from a tape, use a walkman. connect cable from heaphones jack to the line in of the sound card. u can record with any wav editor software. If u are trying to get it from a cd, most of the wav editors can import cd format to wav.(posted 8179 days ago)In order to use this recorded audio into your film, u'll need multi- audio track editing capability in your editing software.
Hope this helps.