Enter any searchable client information (Case Number, client name, SSN, etc) into the All Purpose Navigation (APN) and select the client.
Then select Navigate from the drop-down menu in the next field.
From the next drop-down menu, select Case File
Click on the Green Check Mark.
This will open the Case File in your current tab.
To open the Case File in a New Tab, please refer to the article, Using the All Purpose Navigation to Open the Case File Page in a New Tab.