Hi @kathytran,
That’s smart to use a new learner account to confirm, I find much comfort in doing so 
It seems you have a good grip on Studio and Subsection Prerequisites and it must be frustrating that it’s not working. Is this the first time you’re using Subsection Prerequisites on your platform? If yes, you may want to reach out to your Open edX® service partner to double check it’s working correctly.
Have you seen this post? Enable Subsection Prerequisites is not working - #11 by Sateesh_Kumar
Note: For matters of clarity, the Done/Completion component is not needed to make prerequisites subsections work.