@mohiyodeen:
I just want to know how to setup Pfsense as Firewall in my network? please explain.
https://doc.pfsense.org/index.php/Installing_pfSense
https://zacheryolinske.wordpress.com/2015/04/29/how-to-install-and-configure-pfsense-2-2-2-firewallrouter-for-your-homeoffice-network/
https://www.youtube.com/watch?v=Kq0GiGt4Xf8
Best I can do, given I don't know what your network is like. Even on a basic level, any of these how-to's ought to be enough for you to get started. If you get stuck, post a question concerning the specific problem. Otherwise, links to how-to's are all you're going to get at this stage, I'm afraid.