Two-tier programs exist in the minority of affiliate programs; most are simply one-tier. Referral programs beyond two-tier resemble multi-level marketing (MLM) or network marketing but are different: Multi-level marketing (MLM) or network marketing associations tend to have more complex commission requirements/qualifications than standard affiliate programs.
Ideally, you will already have a website that contains articles and other affiliate offers similar to the ClickBank products you want to promote. If you haven't set one up yet though, don't worry. WordPress is a great free content management system that you can use to start a website and begin publishing articles immediately. Use your articles to draw readers in, then present your ClickBank affiliate offer within the article. You may also want to develop a newsletter for your own website and use it to promote your ClickBank offers to your audience as often as possible. (See: How To Monetize Your Website.)