Where do I enter my inventory into QB Pro?

I just purchase Quickbooks Pro. I have an apparel company and we sell online and at trade shows. I want to be able to track my inventory the best way possible. We currently have approx 30 designs, and they can come in different styles, colors, and sizes.

Where in Pro can I start uploading my own SKU #'s for each item, and when invoices come in for an order I place, can I enter the vendors invoice number, items, my cost, my retail, etc?

I need to be able to basically run this flawlessly without any issues with missing items, etc.

I was told by one of your techs in the online chat that I could do this with Pro, so I am searching the "Sample" version and I cannot find it.

Can you lead me in the right direction? I am using ProductCart V3 for my online shopping cart, and it's compatible with quickbooks for certain. There was just a piece of software introduced that will automatically sync your shopping cart with your inventory, taking out products, etc and making life easier so you don't have to import/export anymore.

Mainly, I need to just know how to start uploading my inventory into quickbooks....OR....is this something my shopping cart software does?

I'm so confused.