When trying to add Process Flow to the Problem Form, going to Configure -> Form Layout and looking on the left side, it is not available.  Also checked the right side but it is also not there.  Confirmed the Process Flow plugin is installed.

Verified in Madrid

There maybe a few reasons this is not showing up.

1. On sys_process_flow table, if there are no Flow Formatters on the Problem table, the Process Flow formatter will not be available to add to the form.
2. Sys UI Formatter record does not exist

1. If Flow Formatters (sys_process_flow table) do not exist, make sure to create it on the table in question.
2. If it does exist and it is still not available in Form Layout options, go to sys_ui_formatter table and filter on the table in question.  If the record does not exist, create the record like this:
   
   This should now allow you to see it on the form layout