The easiest option is to use the tortoise SVN client, which integrates into your operating system. Here you have the import option, which will import your code into the URL of your SVN repository. Be sure to set the tortoise exception list first, so that it does not import all files such as dll, exe, bak, sln etc.
Then do the checkout of the repository to the folder of your project, so that tortoise creates the versioning structure of the code. From here you can start working with your repository by doing commits and updates.
You can also use another SVN client such as Smartsvn or the Ankhsvn .
You can also use the command line to perform these operations.