If you have a file you want to attach to a card, simply drag the file onto the card. A sound icon should show up in the top left of the card. See Main Screen Reference.
Click on the "Play" button and you should hear the sound. Go to the sound menu and make sure the "Play Sound" item is checked. Click the "Show" button and the slide show should start and play the sounds for each card.
There are two ways of recording
sounds.
1) Go to the "Sound" menu and choose "Attach by record...", click
the record button to start then the stop button and then "Save" to finish. You should see the
sound icon in the top left of the card.
2) Go to the "Sound" menu and
choose "Train". The slide show speed should be 3, maybe 4, maybe 5 seconds.
See the Preferences. The when you play the show, it will
record your voice for each card. Click in the window to stop the show.