Woocommerce expert - Product variations and add to cart button not showing up, help!

Kind of design: Custom website
Description of every page: Hi guys,

Woocomerce expert needed for product problem.

www.asilverman.co.uk

Im very new to woocommerce and am having trouble adding product variations so that they show up on my page. I have added in the attributes and variations (Small, Medium, Large, etc) as per the woocommerce guide but they are not showing up on my product pages.

http://www.asilverman.co.uk/product/blast-longsleeve/
for example.

Also, when I add in the attributes and variations, the add to cart button disappears.

I need someone to see if it's me entering the info wrong or a problem with my theme. I need it to be fixed so that the drop down box for each product will display the variations (SMALL, MEDIUM, LARGE, X LARGE) and the add to cart button will show up.

As you can see here - http://www.asilverman.co.uk/product/cohesion-sculpture-2/ - the cart button does show up when there's no variations added.

I need this problem with the theme fixed and a quick written guide as to how to add in product variations properly.

Needs to be completed in a day, two max.
Ideas for the visual style: N/A
Extra notes: