I'm in the process of getting started with an affiliate network (Clickbank), but i'm just a little confused about how the process works. The site I will be using (relationshiphaven.com - ignore the placeholder article) I wish to develop as a proper site, so would it be perfectly acceptable to create a 'landing page' where I have my 'Home'/'Submit Your Question!'/'Contact Us' pages, so that it fits in with the site? Or do I have to use the original 'product' creator's crappy eBook-like landing page - and if not, is it wise to copy some/all of the text content from the original sellers landing page?
You can use both, whatever you prefer. You can direct link to the sales page of the product. Or you can make your own landing page about the product. Yes, you can use some of the content of the sales page of the product for your landing page.