wp paypal shopping cart help

I am trying to figure out how to add shipping into my site. I used this code: [wp_cart:sPRODUCT:price:PRICE:end]

but I need to add shipping. I called Paypal technical support, and they helped me through it on their end and got the html code from them. I pasted Paypal html code into WordPress but it didnt read as a button.

They asked me how to add the weight of each item into the code above – but I don’t know how.

I don’t know the right way to do any of this. I only have 7 items for sale – and the shipping should go by weight.