Customize a joomla template installation

i already have a theme and jombri freelance installed, and i want it to be customised to become useable. the major additions are: -payment gateway([login to view URL]) -pricing page which will load different pricing plans for different design categories when selected. -forms for different design services -discount coupon - user and designer registration forms. The site has 2 user categories: designers and those requesting for Designs,designers don't pay for anything,users will only pay to post their projects:they'll pay(be directed to payment page) after filling in their design forms. Every design category and subcategory has different forms. design categories can include logo,letterhead which will be provided. For the post a project - when user clicks on post a project,he'll see different design categories and sub-categories from which he'll choose which design he wants, then he'll see the form specific to the design(d forms fields will be provided), after filling and submitting,(next step)he'll see the pricing plan for that particular design,when he selects his plan,then next step is payment where u'll link the pay gateway ([login to view URL]) after this he'll login or register. That's it for the post a project. Please indicate these steps with a navigation write up on top of the form page(select design category>>tell us about your design>>select a price package>>review order>>payment>>submit)