A CMS library consists of an OpenVMS directory and its
  subdirectories containing specially formatted files
  that CMS uses.  The library serves as a repository
  for CMS elements and control files.

  When you invoke CMS, you must open a library
  environment to tell CMS which library (or libraries)
  to use.  The library or libraries you specify
  become the library search list.  Even opening one
  library means that you are setting the library search
  list; in this case, the library search list contains
  one library.

  When you specify multiple libraries, CMS accesses
  them in the order in which they appear in the
  search list.

  A library search list can be set in two ways:

  o  By pulling down the File menu, then
     choosing the Open... menu item to
     open an existing library or libraries

  o  By creating a new library or libraries
     (this automatically sets the library
     search list--you do not need to then
     specifically open it)

  Libraries can be viewed in any CMS view.  Use the
  following steps to display a library's attributes:

  1. Click on the library.
  2. Pull down the View menu.
  3. Pull down the Expand submenu.
  4. Choose the Attributes menu item.

1  –  Creating Libraries

  You must create an empty OpenVMS directory (by using
  the DCL CREATE/DIRECTORY command), or direct CMS to
  create a directory, to contain the CMS library to
  be created.  You then create the library in that
  directory by following these steps:

  1. Pull down the File menu.
  2. Choose the New menu item.  This invokes the New
     submenu.
  3. Choose the Library... item from the submenu.

  The New Library dialog box appears, allowing you to
  specify the directory and options for the newly-created
  library.

                         NOTE:
         Once you create a library, you must access the
         library exclusively with CMS commands.  If a
         library is accessed by means other than CMS,
         unrecoverable library corruption may result.