A 'noob' Affiliate Link question/scenario Please advise ; - )

A big "Howdy!!" to all of the learned Warriors here!

I have spent a significant time reading through a decent handful of threads here at the Warrior Forum, and have both enjoyed and learned so much during that time spent.
My thanks to you ALL for the time you spend sharing your experiences and adding your guidance to those of us justing learning the 'ropes' of I.M.

I have had a successful past career in mail order marketing which incorporated an active incoming and outgoing '800' service which sold sportstruck automotive products to the tune of, in our last month in business {this was in the late 90's/early 2000} of gross sales of approximately $6,500,000. dollars per month {most of which was eventually skimmed and/or stolen by the primary financial investor. The entire business concept was mine, while the bulk of the venture capital was his}. This business was a completely 'dropship' arrangement with ALL of our suppliers allowing us to simply concentrate on generating sales instead of diluting our company focus on purchasing, receiving, warehousing, exporting, etc, etc.
So, I have some past experience in successful marketing utilizing a 'minimalist' approach. A business design that Internet Marketing seems to be based upon.

Anyways, I ramble.

Please correct me if I'm wrong but, "Affiliate Marketing" or the use of 'affiliate links' is a methodolgy used wherein one places hyperlinked banners upon your web/blog page complimenting whatever subject it is your web/blog page expounds correct? Visitors click {hopefully} on one of these affiliate link banners once they've become excited enough by one of these products after reading your web/blogs manifesto and proceed to the corresponding website, like the product, and then buy it providing you a dollar value 'commission' from the sale of that product from the company/product you provided on your web/blog.......right?
This is how the money is made, correct?

Assuming this is correct for the moment here is my "scenario"
{the following verbage is fantasy ; - ) }

I create a fairly well laid out Blog on Modern Urban Gardening, within which I want to include a list of affiliate link clickable banners that lead to all sorts of different, independent companies supplying everything from fertilizer to exotic bulbs to specialty gardening tools. From all of which I'm supposed to be getting my affiliate link financial 'commission'.

My question is multi-fold;

1) Do I have to contact each and every company that I want an affiliate link with to ensure they indeed would HAVE and honour this type of arrangement?

2) Once establishing an affiliate link to each particular company, how would/can I keep track of the traffic that goes thru my site/blog and which actually purchases these products, thereby producing my 'commissions'?

3) Would it be potentially out-of-line for me to request from these companies a sharing of expenses regarding the affilate link creation? Meaning, requesting from the particular companies all neccessary line art, copy-ready artwork, etc or would I be on my own in this regard?

4) Assuming these commissions are most usually paid via PayPal or something similar, how quickly {usually} can one expect to be paid these commissions? Weekly? Monthly?

Thank you in advance for enduring my longwindedness, but I am an older business man, and a longtime retired NCO from the United States Marine Corp {proudly serving 1971 - 1975 in the 1st Marine Air Wing} and am just trying to better understand this 'new' technology and terminolgy of Internet Marketing and it's recent focus so that I can continue to stay involved, and stay financially successful so that my grandchildren may never be found 'wanting' in this uncertain economy.

Your patience and understanding in helping me to understand it all is most genuinely appreciated by this old soldier......thanks.

Warm regards to All,

Semper Fi!

USMC_Buckeroo.