Fresh_

I need help because I have a problem on Prestashop 1.6. I am developing an ecommerce with Prestashop. I've made the template, altough on cart and order's pages I've only changed css. As yet the cart and order works fine, but with not correct values because there are not configurated. Now I setted the carrier module and created zones for it. With this, when someone arrives to 4th order step, all values are fine and options carriers and weight too. But when select "Proceed to checkout" the carrier's page (4th order step) is reloaded. Not let me continue to payment. Somebody can help me?