Modify Wordpress Theme

I need to have some features added to my Wordpress Theme (cf. [login to view URL]). The website will be used to offer language courses, so I need some extra code. These are the guidelines: 1. Register system: there will be a “Register Button” on the right side of the Navigation Menu. Users may click on it and fill in a register form. That form will be fully editable through admin panel (with add, edit and delete options). 2. Course pages: there will be a page template for courses, with an “Add Video” option. The video will be located on the left side of the page, while to its right there will be an interactive board with tabs the user may click to see different outputs. In the Edit Page interface there will be a system to add new Tabs to the board and to edit its contents. This is a picture to give an idea of what the page should look like: [login to view URL] 3. Comments: user accounts must be integrated with Wordpress comment-system, so logged users can comment on pages. I also need a more complete editor for comments (similar to the post editor). 4. Product system: admin will have the ability of adding “Courses” to users, so that a user might buy a new course and get access to its lesson-pages. Admin must be able to add, edit and delete “Courses”. The features for “Courses” will be: name, description, permissions (which pages the user will be able to access). If a user receives permission to view a mother-page, by default the “children-pages” should be accessible to him, unless the admin unselects their permissions manually. Feel free to propose new ideas to get the results I need. I will appreciate any pictures and text descriptions of what you think the website should look like and how it should work.