Amazon affilaite - Newbie making authority site - whats next?

Hi,

Have been reading these forums on and off over the last few motnhs and woudl like to create an authority website for a niche I feel has potential (my first site).

- Have narrowed the wordpress theme I intend to use down to a choice of 2.
- Have created about 40 titles that I require articles to be written for.
- Current negotiating with a writer to do all 40 articles minimum 500 words per article.
- Planning on doing the website work myself with the assistance of a few friends who have a bit more experience.
- Once the website is up I am planning to apply for an amazon affiliate account (don't currently have one).
- Looking to release 30 articles all at once and then release the rest and get an extra 20/30 and relase a few a week.
- What would be the next step - I would like to get traffic to the site via search engine I am struggling where to start with SEO (don't mind doing the work and learning) but what programs are worth investing in?
- Should each of the articles contain key words ?
- What is the best method of searching for the key words ?

If someone could provide some direction it would be brilliant, I am confident I can make this work just a bit of assistance getting it off the ground.

All of the questions you've asked has been asked & answered multiple times here, it'd be my suggestion that you do some research on the forum. If you spend some time searching you'll find tons of threads/topics here that will answer all of your questions and more.