add additional steps when add to cart clicked in product info page

I hope I explain this correctly and posted in the proper forum.

Can anyone tell me how I can go about creating this type of product info page on a custom clothing website?

The site at this link http://bit.ly/19iRhuG lists the product, for example, a tshirt, and below the description it allows the shopper to choose quantity and sizes, just like the product attribute grid mod.

And instead of add to cart it then asks you to click on an image (link) that takes you through a step by step wizard to customise your garment and depending on the input by the shopper it then adds the customisation details and additional prices to the shopping cart along with your original product.

I know I can create custom attributes to achieve the same thing but with the amount of different attributes this would require it makes the product page not very user-friendly.

I guess what I need to know is how to pass the product and its price to an external html page and then pass the product and price as well as customisation options and additional prices to the shopping cart page? Would it be as simple as removing the add to cart from product_info page and place it on the external page?

Please someone help me or point me in the correct direction?

That looks to be a bespoke custom code

kobra:

That looks to be a bespoke custom code

I don't think it is a zen store but I want to be able to implement the same steps into my product_info page. I know html and css and how to carry sessions between pages in php. I don't know the zen cart structure all that well though and would need advice or a point in the right direction towards carrying the information regarding the product and price through those sessions and then at the last step when the customer clicks add to cart it then adds that session as well as the other information collected to the cart?

Or can anyone suggest a different procedure that I haven't thought of?

I don't know the zen cart structure all that well
This type of customization will require a good bit of custom code - javascript -
So you would be better off hiring it done