Sentoz is a free premium WordPress theme. This is a tumblog style theme. The theme uses WordPress post format feature to create posts with different formats like, image, audio, video, link, aside, gallery, quote etc
The theme often requires few plugins to work the way it is originally intented to. You will find a notification on the admin panel prompting you to install the required plugins. Please install and activate the plugins.
The post format ui plugin will give a nice an intuitive interface through which you will be able to post different post formats.