7 – KickStart Ecommerce Customization

My business model is different. I want to create an e-commerce website where physical store owners can post their products on my website. I've managed to install Ecommerce kickstart but I do not know how to make this feature work. Basically, I have to create three user roles:

Web Administrator (me)
Store Owners
Customers
  1. How will I make the store owners unable to edit the products, the type of variant, the content he does not own?

  2. How to create a registration button for store owners? By default, the registration button is for customers.

Any idea will be appreciated.