Step by Step easy installation guide:
Via Magento admin panel, go to magento connect manager, and install the extension using the extension key (The key which you got in the Magento Connect site, on the extension page).
After installing the extension, go to "System->Configuration" and click on "Winbuyer Configuration" on the left side bar. There you will see a "Required Parameters" section. Please fill in a Campain ID which you got from WinBuyer. If you don't have a Campaign ID, you can register and get it here: http://partners.winbuyer.com/merchant_join.aspx?kw=magento&c=6001090
After filling your Campaign ID, and refreshing the cache, you should see the "Related Product Listing" on your Magento Store product pages.
1) I installed the extension via Magento Connect, and now when I go to the admin panel configurations, I see 404 error. -> Try to log out of the admin panel, and log in again.
2) I installed the extension, filled in my Campaign ID, but I still can't see the "Related Product Listing" on my Magento Store product pages. -> Please ensure that the Campaign ID and the domain where you installed the extension match the Campaign ID and the domain name that you filled in your WinBuyer account.
3)I acomplished the section 2 suggestion, but I still can't see the "Related Product Listing" -> Check that the "Enable WinBuyer Related Product Listing?" setting is "Yes".
4)I still have problems to see the "Related Product Listing" -> In which language are names of your products written? If the language isn't English, the extension may encounter a trouble to run.
5)I still have problems to see the "Related Product Listing" -> please contact WinBuyer support (http://www1.winbuyer.com/company/contact-us), they will be really glad to help you.