Below the synopsis, page count and language etc, there will be this: Report incorrect product information. Click on that.
Then a window opens where it asks for details, pick: This product or content is illegal, unsafe or suspicious.
Then it asks for the issue, pick: It uses my intellectual property without my permission.
Then this appears: To report infringement issues, go to Public Notice Form.
You can click on 'Public Notice Form'. A new site will load. Click on Report Infringement in the top right corner, right beside the amazon logo. Scroll down after clicking on it and click on Start Report. Have the URL of the product ready or just write down the name of the product in question. Then just fill out the field about the issue and if possible provide a link to SH or RR or other sites, so amazon can check if you really are the author.
You will have to write down your name and other basic contact information. Important: Your real name, email and phone number will only be seen by Amazon, not the other party.
They will ask you for a second email which the other party (the person stealing your stuff) will get in case they want to contact you. You also do not need to give them your real name.