In order to use Subversion from the winIDEA it has to be first enabled in the File / Source Control / Settings. Read this article to learn how to correctly install all required SVN components.
Source Control Settings dialog
SVN controls are now available through File / Source Control menu:
Source Control controls
Files in the Project Workspace tree are marked with blue ticks if they are unchanged and with red ticks if they contain changes. For SVN manipulation of specific files select the files from the tree and open the context menu. Depending on whether the file was changed or not the context menu will offer appropriate SVN commands:
SVN Commands on an unchanged file
SVN Commands on a changed file