I'm not exactly sure what someone else told you do, but there are a few things you may want to do before posting any products.
- You will probably want to make certain that your policies are clear and easy to read.
- You will want to set up a shipping profile or two so you can pick the one that best fitst your product
- You will want to make certain that all your shop information is clear.
- If you plan on setting up different sections for your store (some use it to organize their handcrafted goods into different groups making it easier for people to browse your shop) then you'll want to set up your sections so you can put products into those sections as you add them to the site.
Just a small list, but I am sure the community will have more things they can suggest.
Also, never hesitate to ask questions, no matter how many questions you have. It's what I am here for.

In fact the entire community is here for it!