CODESYS SVN is a comercial extension of CODESYS, which costs some amount of money. But to use it with CODESYS Forge, you can simply download the CODESYS SVN package and install without a license. If the package does not find a license, you get unlimited access to all repositories on CODESYS Forge.
All you need is an account on the CODESYS Store, and you can download the most current CODESYS SVN package.