I am unable to decipher exactly what youa re asking from your post, but try the oscommerce forums and site, they have boards for support and since the package is open source there are many add-ons to choose from on their site.

The best way to really learn osCommerce is to download the code and set up an osCommerce test site. You don't have to sell anything, but you do need to learn to work with the code.

osCommerce is getting pretty old and decrepit. Most developers that I know gave up on it quite a while ago because it is not being updated and the support is in hopeless disarray.

Zen Cart and other shopping carts are light years ahead of osCommerce when it comes to updated code and support.