Welcome.

Check the Software forum topic for the downloads.

It can be used with one computer, monitor, mouse and keyboard.

You can dual-box with 2 accounts.

It doesn't take uber-leet computer for dual-boxing. Need more power or multiple computers for triple and beyond.

Blizzard has approved multi-boxing many times. No one has been banned for legitimate multiboxing. Just be sure all accounts belong to you. Don't use friends accounts.