Repository and working copy
To be able to use this guide, you need to be familiar with the concepts of a repository and a working copy.
Repository
A Subversion repository is the central storage that contains all the files for your project, along with the version history of those files. This version history makes it easy to track the evolution of your project over time and to roll back changes. Typically, to facilitate collaboration between multiple people, a repository is stored on a dedicated server computer to which users connect over the network.
Working copy
To edit files stored in the repository, a user first downloads (checks out) the content to a local working copy. The user then makes any desired changes in the working copy and commits those changes back to the repository.
In Subversion, it is quite typical for a user to simultaneously have multiple separate working copies checked out from the same repository. These working copies may be checked out from different branches.