From the Home page, click Tools, and then click Variables.
Select the User Variables tab.
Click (Add).
A new variable is added to the bottom of the list.
Scroll to the bottom of the list and click the down arrow next to the Dimension name for the newly added variable. For Select Dimension, select the dimension for which to create a user variable (including attribute dimensions).
In the User Variable Name column, enter the name of the user variable.
Click (Member Selector) to select dimension members.
Note:
The Use Context setting means the value can't be
chosen by the user from user preferences. Instead, the value is passed
from another form based on its Point of View context and the value will
change dynamically based on the context of the form. However if the user
variable is used elsewhere, such as in rows and columns, you must create
a different user variable so the user can set its own value for it
because it won’t be set dynamically.