The
Dosbox Tutorial will give you a hand with the window size, and how to change it.
For the sound go into setup.exe and change to Sound Blaster Pro 2, just press enter when it asks for details of your sound card, the default settings work fine.
On the note of installing it, you shouldn't be installing the game, just unzipping then folder into your games folder, (inside its own folder that is) and mounting your games folder as normal. And what instructions did you try and follow, I couldn't find any one the main page for Seal Team, just a note that it runs slow in Dosbox, which is no longer true.