Welcome to E-junkie! :^D
The various settings and some approaches to using them are described in our help pages indexed here:
(...also available under the "help" link in blue along the top of our main Sellers pages :^).
As a general rule, it's safe to assume that if you don't recognize what a particular setting is for, then you probably don't need to concern yourself about it. We have quite a few settings that only address a very particular need, and if you try to learn about them all first before you do anything else, things could start to seem a bit overwhelming and confusing.
Just focus on what you want to do -- the actual result you want to accomplish -- then see if you can figure out how to do that, and feel free to ask questions here or send us an email if you need more explanation or advice. We're always glad to help out and point you in the right direction. Here's a good starting point to get a general understanding of how our system works and how to start configuring your cart and products: