The two-part checkout/checkin process extends a branch of an element version tree with a new version. The first part of the process, checkout, expresses your intent to create a new version at the current end of a particular branch. The second part, checkin, completes the process by creating the new version.
For file elements, the checkout command creates an editable version of the file in the view, with the same contents as the version at the end of the branch. Typically, you edit this file and then check it back in.
For directory elements, the checkout command allows file elements, directory elements, and VOB symbolic links to be created, renamed, moved, and deleted.