By default, the Tweet text is shown at the top of the Tweet, above the image or video element. You can swap their position by adding this to the plugin’s Custom JavaScript section (Twitter Feeds > Settings > Feeds > Copy the JavaScript snippet below into the Custom JavaScript box, then save the changes.):
$('.ctf-item').each(function(){
$(this).find('.ctf-tweet-media').after( $(this).find('.ctf-tweet-text') ).css('clear', 'none');
});