Setup Source Control within GameMaker:Studio

What is Source Control?
Source Control is the name given to the method of working with sub-versions using the free licence Apache Subversion (often abbreviated to svn), which is installed in the form of an independent software package to control all the aspects of maintaining, changing and comparing versions of your game as you work on it. This is especially useful to those that work in a team and need to be able to control who does what and not worry about losing data or making changes that may need to be undone at a later date, but individuals can benefit from this powerful yet flexible system too.