Iteration Multi-instantiation

Hello,
I have a process that start with a form for creating a list of users from the DB. Then for every user in the list I would like to send a form to fill out. After all of them are done, I send the process to a review task.

My first question is if I am doing right with this approach or I need to work with a loop, or maybe a subprocess.

The first form has an autocomplete field for getting the email of the users and an "Add" button for adding users to the list

http://community.bonitasoft.com/questions-and-answers/how-use-autocomple...

when the form is submitted, the users are saved in the BDM . So then I need that every user in the list to complete the "Fill Form" task. Every user is filling out its own form. The process must wait till all of them are done and then continue to the "Review" task.
I understand that I have to do something in the General>Iteration panel but I don't know what to put in there, how to bind the users with the list, how to configure the users in the list as the next actors, etc.
Could somebody help me with the steps for doing this? Thank you!