These are all the basic steps that you can take to list your first products. You can make a template as well and just click duplicate, once you have made your first few! Adding products will become faster and faster because of the way that this site has been set up. You can be as fancy as you want and add lots of information or just follow the basic (and very detailed) step by step guide below.
This tutorial may seem long because of the amount of detail I went into, to make sure I can answer all the questions you may have. Alternatively you can view the video tutorial.