Open up the Administration tool, go to Manage then variables.
See screenshot below.

variable manager
Then follow this picture to create a new Initialization Block.

create init block
Name your Initialization block init_block_test.

big picture

B: Click Refresh All from the Oracle BI menu in PowerPoint to refresh all the refreshable objects in the presentation.
C: Right-click Table and select Insert as List from the shortcut menu. The Edit Prompts and Levels dialog box appears. Accept the default options and click Insert.

Identity Store: It is directory server to perform the authentication. It contains user name , password and groups membership information .When a user name and password combination is entered at log in, the authentication provider searches the identity store to verify the credentials provided. See figure below.

Screenshot below.