To add a preview, start typing a keyword in the preview box and an auto complete option will appear with search
results. Click on the track which is your preview. Screenshot example below:
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When the preview file has loaded you can click the play icon to play the preview.
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Note that the auto complete only starts after min 3 characters are typed, to change this edit the 'AUTO_COMPLETE_MIN_LENGTH' value in the
'control/options.php' file.