How do I edit game sound banks? Thread

Recently I was looking through the files and folders of all the PC games I have (downloaded from Steam). I noticed that in some cases I found MP3 files, and presumably all I had to do was take my own sound, rename it to the same name as the original sound I want to replace, and delete the old one. This was generally only the case with basic games though. The Bioshock demo , differently, contained a small number of files with the extension '.fsb'. I briefly Googled this, and it seems these files are something to do with Fmod. Oddworld: Abe's Exodus had what I thought to be a pretty simple sound scheme that would be a good start for me, but the game folder only contained a single file named 'sounds.dat'.

Now, I have Wwise installed and have spent a few hours learning the basics a while back; I knew Batman Arkham Asylum to have used Wwise, so I downloaded the demo in the hope I might have the tools to work with this one, opened up the folders an found a folder entitled 'SFX', which contained extensions '.bnk'.

In any attempt at opening these files, I've been presented with text gibberish. Treat me like a noob/idiot if you must, but I'd really just like some idea of where to start here? I don't know much about how game engines/ audio engines work, or what other files in the game folder may be relevant to the tasks I am trying to carry out.

Any soloutions to either of these games' file extensions would be highly, highly appreciated, however I'd be more grateful for a solution to game audio pretaining to Wwise, because if possible, I'd like to be able to edit FX, attenuation curves etc. and Wwise is the only software I have even a clue how do do this in.

Thanks! =]