When a Resource is under Version Control, a new copy is made each time the resource is checked in.  A Version History is displayed as a new pane in the Info panel (or Info dialog).  Select the Resource in the Document Tree and examine the Version History pane in the right-hand panel of CERF (Info).  Right-click on any of the Versions in the Version History to carry out actions such as View.  If you edit one of the Versions, a new branch is created.  Similarly, if you copy and paste a resource as a version in CERF, this will start a new branch.  In addition to Version Numbers and Labels, the Version History shows comments, Contributor (whoever made the changes to the resource is the contributor), and Date.

A resource can be put under Version Control at the time Metadata are edited or at the time of Check In using the regular "quick" Check In button  when business policy defaults are in place (or by using Full Check In   if the business policy has been changed). 

When editing Metadata, the Version Resource dialog is launched when you click on OK on the Edit Metadata dialog.  When checking in (using Full Check In) the Version Resource dialog is launched first.  To create a new version, select the radio button for Save as New Version.  You may enter a version label and comment (optional) and select where the updated version will be displayed (generally you will want it to be shown in All Collections).  Click OK. 

Another way to put a Resource under version control is to copy and paste is as a new version in a new location.