Where can I find more about the affiliate program?

Hello.
If by code you mean an access key you can find it in your CleanTalk dashboard. The access key to each site is hidden under the “key” sign on the page listing your sites.

Please, read this guide, it should help: https://cleantalk.org/help/affiliate-program.
Any further non-plugin questions as per forum rules please ask in a private ticket system: https://cleantalk.org/my/support/open

Please let’s continue our conversation in our ticket system. WordPess.org Support Forum is for plugins only, not the paid service.