Run apache server but cannot move forward port 80

I want to run an apache server and I watched a video tutorial to do so that says to move port forward port 80 to run it properly. I have tried doing so but in vain. I get locked out of my router and then I have to restart it. The router I am using is FiOS Actiontec SFU Model MI424WR-Gen2. Pls tell me how to solve this issue.
