Add product to cart in MijoShop (OpenCart)

Hi, We need to find a freelancer to handle this problem: We need to add products to cart directly, without clicking the add to cart button. We have some akeeba subscriptions that are related with products in MijoShop. Each subscription is a product in the store. To find the appropriate subscription, we have a form and depending on people's answers we trace a profile and then we want to add automatically the subscription to the cart and redirect directly to the checkout. All development is already done, except the add to cart function.