General step by step on how to create a store with the same architecture/functionality as

Basically i want to clone to some degree. I would like a general 1,2,3…guide to follow on how to proceed and what plugins I should use… I will ask questions later if I cant figure the steps out. Here is generally what I want to accomplish: Use the Product theme as the main hub if you will. I will then allow users to create their own sub stores (blogs) with limited functionality where basically all they can do is post products that they have and will sell and ship. I want global shopping cart functionality as well and the ability to sort what is shown on the hub portfolio (using the portfolio as the homepage) based on categories. Get me started in the right direction please. Thanks!