Checking out SVN
What is SVN?
Subversion is a framework or versioning control system used for Scribus. As such, it allows multiple developers to contribute to the Scribus source code simultaneously, and for our purposes here, allows anyone to keep up to date on the latest code with has been committed to the project. Check the Subversion page for further details on how to use this tool. On your computer, subversion is a program you must have to interact with the Scribus repository (the server where the source code is located). Therefore, you must have svn installed, and you must be connected to the internet for subversion to work. Most users, those not contributing to Scribus, will need only 2 commands, svn checkout, which has a short form of svn co, and svn update, which has a short form of svn up.
What is happening when you checkout the source code with svn co is that you are downloading all of the elements of the sourcecode, which is a large number of files split into a number of directories. Therefore, you should understand something about how directories and files are arranged on your computer. On the server, the top directory is Scribus, with all the files and subdirectories inside, and this structure is duplicated on your computer. Once you decide to update your source code, you need to be inside this Scribus directory, so that then you can run the svn up command. If you are not in that directory, updating will fail.