This is the weird one. In the beginning of 2017 there was no tad or a section in Pardot where you could add a Salesforce Queue. What is the reason for adding a Queue in Pardot?
One of the common use cases would be to create an Automation rule and every time new Prospect is submitted via Form or Form Handler it would create a Prospect in Pardot and automatically assign it in Salesforce to a Lead Queue.
I used to access Pardot Queue setup by using this link - https://pi.pardot.com/queue
Then I would click on "+ Add Queue".
Select available Queue from the dropdown and the click on "Create queue."
Now the process seems to be improved, but it can be hard to find it if you don't know where to look for or you are new to the system.
And if you scroll all the way down, you will be able to find a queue setup there. :)
I hope this was helpful.
If you have any questions, please do not hesitate to get in touch. :)