Port Forwarding.

I know these forums have probably seen 10,000 Port Forwarding help requests. Here's mine. I've google'd it. All I've found is ones explaining how to download a program to do it. Last thing I'm going to do is download a program that i don't even know or trust. I have access to my Router and I just need someone to link me to a Youtube video or a detailed and trusted explanation of how to Port Forward.

Thanks,

Nick.