OpenSSL and "Home-Brew" Cert Creation

I need to make an SSL cert. for our Apache web servers at work. It's going to be a home-brew cert, so alerts about the certifying authority aren't an issue. I have a key and a certifying authority file that were generously left behind by the last guy who did this. So how do I do this? What are the steps using the "openssl" command? I've been reading through a lot of documentation, but it seems unclear.