Blackmagic RAW Speed Test - how select drive ?

Boy, I must be missing something pretty obvious, and I am too stupid to see.
When you launch Blackmagic RAW Speed Test, and you click on the Gear icon, can someone please tell me where to select the drive you want to test ? I find it hard to believe that it will only test the boot drive of the computer, and not the external array, or external network storage.

Thank you -
Bob Zelin

It's not testing drive speed. It's testing CPU and GPU performance.

Just in case anyone still tries this in 2023...

There are two different Blackmagic apps - Blackmagic RAW Speed Test and Blackmagic Disk Speed Test.
Disk Speed Test has the option for selecting target drive when you click on the cog.