1. Reference Name: I prefer to use the ensemblesecuritytoken.email value generated from the process manager login component. This comes from using ServiceDesk which uses that value for contacts. I believe in theory though, you can use pretty much anything you want (i.e., user's first name space last name) but if you want to report on that data later, you'll want it to be consistent.
2. Reference ID: Use the ensemblesecuritytoken.userid value.
3. Reference Type: Choose constant value instead of a process variable and select 'user' from the drop down menu.
4. Contact Type: Whatever you want, really. This tends to be hardcoded to a constant value based on where the 'add process contact' component is being used. For instance, I have a new software request workflow that adds several contacts (not directly in a row, mind you). The first one is right after the user submit's the request and that user gets added as a contact type 'Submitter'. Once a technician has approved the request, that tech gets added as 'Approver'. This is really a free form field that you should use to suit your particular workflow. Again, be consistant if you want to report on it, especially if you want to bring it into existing ServiceDesk reports.