Can't find any information online about what connections the Tatasky HD box has.
If the box has HDMI and optical audio output then I would connect the HDMI to the TV and the optical to the HTS.
If the box has a coax digital output you would need to convert that to optical.
If the box has audio output you would need an HDMI inputs selector with audio extraction.
These will give you digital surround sound.
The other option is to connect the box to the TV with HDMI and connect the audio output of the TV to the HTS.
This will work but you will only get analog surround sound.