Hi,
sorry for late reply, it's a weekend
Normally all templates allow you to add custom Javascript code with 2 ways:
1) In Template parameters (Extensions->Templates->Styles)
2) In specific custom files, for example creating a new file like /templates/theme-folder/js/custom.js
About your template you can follow docs at
http://documentation.aplikko.com/flex/#Custom_Code_Settings, in parameter called "Before /head" add following code:
<script>jQuery(document).ready(function(){
jQuery('#sppb-addon-1553937077636 .jsn-l-row').hide();
jQuery('#sppb-addon-1553937077636 .jsn-l-row').first().show().addClass('jsn-active');
setInterval(function(){
if(jQuery('#sppb-addon-1553937077636 .jsn-l-row.jsn-active').is(':last-child')) {
jQuery('#sppb-addon-1553937077636 .jsn-l-row.jsn-active').hide().removeClass('jsn-active');
jQuery('#sppb-addon-1553937077636 .jsn-l-row').first().fadeIn().addClass('jsn-active');
}
else {
jQuery('#sppb-addon-1553937077636 .jsn-l-row.jsn-active').removeClass('jsn-active').hide().next().fadeIn().addClass('jsn-active');
}
}, 3000);
});</script>