Prestashop module customization

Introduction - I’m building a simple classifieds website using a Prestashop module. I bought a module to give to the users the opportunity sell their products in a simple way. The problem to solve is that now the signup and the product publication process is to long and a bit complicated. So, what we need is a customization. From a module we use you have to create a new one-page to signup and post a product to sell, with other customization required. Please read carefully the document and pay attention to all the customizations required. The project in 4 steps (more details if interested) 1. Page creation: Create a one page for the signup and a product publication, customizing the existing marketplace module. 2. Home page, search engine customization: search engine and home page. 3. SERP page (Search engine results page): customization of the serp page 4. Back office and data