there is no 1 way to create an eCommence website. It is a project that can be approached a variety of different ways. see the web development workflow for a starting point:
It really depends on what features you want to have in your site. you mention and admin page to add products so that is where I would start.
1) Crate the Database for the site. the structure needed will depend on the features you need for your site. We offer the free eCommerce database as a starting point:
2) Create the security Assist registration login system. Since you plan to have an admin section, add user level authentication. There is an older tutorial for user level authenticvation here:
it was written for V1, but the concept is still the same.
3 - 4) Create the Product admin pages. this is done by running the Data Assist wizard to create search, results, insert, update, and detail pages for the products table. I like to create the admin pages in a separate sub directory. you should then use security assist to protect access to the product admin pages to only the admin user.
Next Create product catalog pages. Use Data Assist again, this time create only the search, results and details pages:
5) Now add eCart add to cart buttons to the catalog pages:
6) After the add to cart buttons are added, you c an add checkout by running the eCart checkout wizard.