Where is the "Add script..." tab under file that is mentioned in the wed programming tutorial? I can't find it.

may be under File|Map Prop.
save map at first and open Map prop-s dialog.
you can add script to map there.

Thanks. If anyone knows anything about this tutorial, it also comes with a map. The tutorial says there is supposed to be a player model but there isn't. I'm a noob, where can I find a model to use as the player model?

for a first time install of 3dgs look under [install folder]\work or try to search any files with the .MDL extension.
try to use cbabe.mdl, for example.