Problem with Firewall

I have just downloaded and installed a copy of the Comodo Firewall as I had had it highly recomended by a friend. All went fine and after install have the message under system status that the firewall is not functioning properly.As suggested I ran the Diagnostic Utility which found no problem. I did look in the forums for help but the advice got very techy quickly and I soon felt out of depth. If someone could explain to me in words of one syllable what to do I would be v grateful as I do want to persevere with Comodo.

Welcome to the Forum, jmeister2009

First, we need basic information to help us:
What OS (Operating System) are you using, what version of CIS, any other security software installed/active.
You may have to do a clean install with you existing AV disabled first.