From the Categories menu, click Versions while viewing the properties for a requirement.

The Versions page column details are as follows:
Select Box. Click the column header box to
select all versions. Click the row box to select one or more versions.
Version Id. The revision number of this version.
Description. The description of the version.
Owner. The owner of the version.
Modified. The date on which this version was
created or last modified.
Content. Any content text about the version.
Priority. The priority of the version object.
Classification. The classification of the version
object.
Use the Actions menu or page toolbar to work
with versions:
Create Version. Create a new version from scratch.
A new version is created from the main requirement revision and its Version
Id is automatically incremented.
Roll Up. Click to roll up a version. See Rolling Up Requirement Versions.
Structure Content Editor. Click to view versions
in the Structure Content Editor. See Structure & Content Editor.
Delete. Removes all checked versions from the
list and deletes them from the database; select OK
to confirm.