You don't actually make money on Clickbank. Clickbank is just a payment processor for vendors and a tracking service for affiliate commissions. When people talk about making money on clickbank, the actual marketing model being discussed is Affiliate Marketing.
There definitely are some specific things about Clickbank that do make it easier to find good products to promote, but if you want to succeed it needs to be kept in mind that the actual products you choose to promote that will make you money. All clickbank will do is track those sales for you so that you'll get your commissions.
So if you want to make money online, then Affiliate Marketing is a good choice to work on. To learn how to do it right just follow the advice OnlineGodfather gave you above. But you may need to look through other sections besides just clickbank. Look through the forums for threads on these topics.
Then outline a plan to follow in this order.
1. Choosing What to Promote
- a. Selecting a good niche.
- b. Selecting good keywords for the niche.
- c. Selecting a good product relevant to those keywords.
2. Building A Website to Promote
- a. Selecting a good domain name. (or blog name if using free hosts)
- b. Setting up a website suitable for your product promotion.
- c. Choosing the best types of content for your promotion. (sales pages, review articles, etc.)
3. Generating Traffic for your Promotion
- a. Types of direct promotions to generate immediate traffic
- b. How to promote your website for search engin traffic.
As you get going you'll also need to look up topics regarding how to evaluate your results. If you don't succeed right at the start, it doesn't mean that Clickbank didn't work for you. It just means that something in that above list isn't right. Affiliate marketing is a time-tested system of making money online. When it doesn't work for someone, it's important to figure out what part of your campaign need to be corrected.
So, choose the right niche and product, set up your website correctly, generate the traffic. If you get all of it right then you WILL make money. Get any one of those factors wrong and you'll struggle with it.
Good luck.

~Wolf