Help converting HTML/CSS files to Shopify's Liquid

Hi guys
I recently purchased a theme called Flipmart from Themesground for the aim of developing a store using Shopify as my shopping cart platform. But i sadly found that Shopify uses a Liquid Engine for their templates. So now i have to convert Flipmart’s html/css files to .liquid extension. May anyone please assist me in any way on how i can apply this theme template on Shopify. A simple tutorial will help me alot, i cant seem to find one online.

I tried contacting the author but he has been of no help.
Regards