There are a number of threads in this forum covering a number of workflows with the Forms Gramplet.
This thread has an example of setting up the 1950 US Census via an import. (Either with the Import Text gramplet or via a file import.) It creates a sample Person (the actual Director of the Census) that you can use as a reference.
There are also 2 Gramps Video Tutorials about using Forms that were created 2016 for version 4.x too.