Help Updating/Upgrading

I am trying to update my WordPress from 2.6.3 to 4.0, but can’t seem to get anything to activate when I download never versions, whether 2.6.5 or 2.7.1 or 4.0. When I look for instructions it tells me to edit wp-config-sample and it seems to want some database information. Is there anywhere on my wordpress site that can tell me where to find that kind of information?

I am managing a podcast that I did not setup and, while I might be able to ask the original creators for info, I don’t know the ins and outs of wordpress and don’t know what sort of info I am looking for.

Thanks!