First, let's discuss some
basics. Dungeon Siege stores game data in
archives called "tanks" - a play-on-words from the company name, "Gas
Powered Games". A similar play-on-words is done with template files,
which are called "gas". Get it? Gas? Tank? Ha-ha, we're rolling with
laughter, yes.
In any event, these archives are much like "zip" files, except that they
have a somewhat different format. Opening them requires one of two
tools - either Siege Editor, or TankViewer. As TankViewer is by far the
simpler of the two tools to use, we'll be working with that. You can
download it here.
Once you have downloaded and installed TankViewer, open it. You'll see a
screen that looks something like this: