InfoPath Dev

I've been looking around and can't quite get the right answer... If a user selects 'Pass' on a drop down I need a free text field to appear underneath so that they can add additional information. Can someone point me in the right direction? Thanks in advance

 How many options are in your dropdown? If not many here is what I would do:

Create a section and place this free text field inside of it. Make a formatting rule to hide the section if your dropdown field was equal to all other options beside "Pass"

 

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Hi Chris Could you post the screen grabs again? They aren't showing up. I get the theory just would like to see the logic on the rules. Thanks

 I uploaded a zip with a word doc inside that has everything. Its under the Options tab, I couldn't get the snipits to display for some reason