Please see integration section in the help page.
As a general rule of thumb for E-junkie, you should not use any feature that you don't need specifically as that will only complicate the process and might overwhelm you. All you need to add a basic product in E-junkie admin is to enter it's name and price.
Once you get the button code and paste it in your website and have got that going .. then you an start playing with various product settings.
