As George says, there is none.  There's no user guide or contextual help available in or for ProConnect Tax.

You can, however, find some pretty detailed instructional articles for various tax forms here: https://accountants.intuit.com/support/en-us/proconnect-tax/help-topic/view-all-articles

These articles are not exhaustive but do give you a good sense of how ProConnect Tax operates. 

There are, nevertheless, limitations that Intuit does not advertise.  If you ever feel like you have run into a wall, feel free to come back here and someone will be able to give you some pointers, validation, or workaround.