I need to create an ecommerce website but i have no knowledge about websites and how they work?

[Frank]

It is actually really easy to get it set up. I recommend using wordpress for the framework and using some basic shared or dedicated hosting depending on your budget. Perhaps start out with shared hosting and upgrade when it's necessary.

Here is a step-by-step tutorial to set up WordPress:
http://stuffsz.com/how-to-make-a-website/

Then just install WooCommerce which easily allows you to add payment methods, products (with all options like shipping, tax etc). You can get it here:
http://www.woothemes.com/woocommerce/

Both WordPress and WooCommerce are free and easy to set up. It is really easy to add WooCommerce to WordPress just add it to the plugins folder and click enable!

I hope this helps!