Well, here's what I can tell you, others will certainly fill in the gaps:
It's a text file consisting separate pieces of information, separated by some sort of separator character -- tab, comma, "pipe" ( | ) symbol, etc.
Datafeeds are supplied by the vendors.
is arranged in rows and columns. Usually the first row holds column names for all that follow -- names like prod_name, prod_descr, image_url, etc.
Each horizontal row holds the information for one product, scattered among the various columns.
The data is primarily used to generate one web page for each row's worth (one product's worth) of information. This can be done automatically by various programs -- WebMerge etc. -- or it can be done by programs or scripts you create yourself.
Some people just use the datafeed as a handy source for making links that's got everything in one place. They'll just open the file in NotePad or another simple editor and clip out the link URLs and similar information that they want and manually copy it into their web pages.
Some vendors supply free datafeeds, and some vendors and/or networks charge us for them.
2) Getting traffic:
Many folks just create their pages and then submit them to the search engines. Click on the "Tools" section of the toolbar at the top of almost any page in ABW -- it's at the right end. There you'l find search engine submitting tools.
Other folks pay for clicks -- I'd think doing a search of ABW for "PPC" -- pay per click -- using the "Find" link on the ABW toolbar will give you lots of information on that.
3) Tips on website building (nice ones):
I'm a bad one to talk about that, my pages are always very plain and simple.
I follow Leader's advice to keep your pages simple so the visitor won't have anything much to do there but read your text and then click through to the vendor's pages.
I'm sure someone else will be able to suggest their favorite books on website and page layout -- I know I've seen that question answered here before.