Source Control (Revision Control and Version Control are other names it does by) is simply the art of being more organised and secure with major projects.
A simple method of Source Control is having a backup '__.old.__' file to fall back on in the event that you lose your or cause your current files to become corrupted, adding a version number (01, 02, etc.) to each version of your projects to identify them easier and using a shared folder VIA Cloud Save using something such as One Drive or Google Drive.
However, for much bigger projects you shouldn't glue yourself to the above method, use a Source Control System. This allows many people within the same project to work on individual parts and then contribute this to a full project, taking out, updating and putting back in as they please. GitHub and BeanStalk are examples of an SCSs.
SCSs allow for many benefits such as Backing Up And Restoring things to a specific date and Long and Short-Term undoes.
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