Hi miray,
association between cockpit and analytical drivers is made by adding them in the document edit view (Documentation ref: https://knowage-suite.readthedocs.io/en/7.2/functionalities-guide/analytical-document/index.html?highlight=add%20driver#association-with-analytical-drivers). Please make sure your document is correctly configured.
Just to let you know, the Variables tab is used to create useful variables for use within the cockpit widgets. (Documentation ref: https://knowage-suite.readthedocs.io/en/7.2/functionalities-guide/cockpit/index.html?highlight=variables#variables)
GreetingsAlberto