Hi tomer628,
did you know that Plesk provides as well online documentations about Plesk and it's components?
If you need help here, pls. try to describe WHAT you did, WHERE you are stuck, or try to describe your possible issues/errors/problems, so that people willing to help you have something to start with their investigations and they might then be able to provide possible solutions/suggestions regarding the Plesk Firewall and the usage of "iptables" on your server.