You might need to access a particular Snapshot copy (a version of a file at a particular point in time) because a file was changed, corrupted, or erased and the problem was not noticed until after one or more Snapshot copies of it were created. When you start looking for the version of the file you need, you will look for it by means of the access time of the Snapshot copy.
The version of a file refers to the last time the file was modified before a Snapshot copy was created. The access time of a file refers to the Snapshot copy creation time for a file, whether or not any modifications were made to that file.
The best way to find all versions of a particular file preserved in Snapshot copies is to use the ls command from an NFS client, or to use the Find function in Windows.