No step by step guides, I'm afraid. Normally, Mac software doesn't need complex installation instructions - just follow the maker's onscreen steps.
You *can* put it in your home directory, I guess, but it will only be available when you are logged in as that user. If you create another user account for any reason it will not be able to access Civ4. I haven't tried it, but I guess the patch system *may* also have difficulty with user permissions when it tries to modify the software.
A lot of people, me included, just put the Civ4 software folder in their /Applications/ folder, where most other software goes - it's the equivalent of Windows' Program Files directory, and is where most patch installers expect to find your applications. Some people who have lots of game software may create a folder called Games, either at the top level of their hard drive, or inside /Applications/, and install Civ4 there.
The Aspyr patch installers are not the best engineered items ever to hit the Mac software market. You'd have to ask Aspyr (without the 'e'

) why they don't mention bugs on their site, but you will be unlikely to get an answer from them here, as they never visit these days
