To use SVN clients, you must have a SVN repository where the sites you use should be stored. Having a SVN repository, you can get from it one or more local working copies of any resource from that repository. For this, you must do a checkout operation from a SVN client, like Syncro SVN Client or any other SVN client. By doing this operation, the new local working copy will have the resources you wanted. In every folder where the resources are will also be a folder ".svn" in which is stored information that are used by SVN to work properly.
Now, if the local working copies you say you already have on your local hard drive were created using a SVN client, then in Syncro SVN Client all you have to do is to use the Add/Remove Working Copy from the Working Copy main menu of the application. In the displayed dialog you should hit Add and select the local SVN working copy folder to be added. After doing that, Syncro SVN Client will know what is the repository from where those resources where copied, because of the internal information from the ".svn" folders and there should be no problem.
If all of the above steps are the steps you do, then you should provide us some more information to know what is happening exactly, like:
- what operating system do you use and what is its version;
- what version of Syncro SVN Client do you use;
- with which SVN client where your local working copies created;
- what are the exact steps you do (what options you choose, what actions you do...);
- are you having symbolic links in the resources you have on you local working copies?
If the local working copies you have where not created with a SVN client or they are copied only as simple files (like copying files in a file explorer) then you cannot link them with the server using SVN and for using a SVN client you will have to do the checkout operation, which means downloading them again to have the ".svn" information folders.