Detailed help files are available in the map editor.
Custom scenarios are called PUDs, and can be exchanged from system to system. Windows 3.x users can run the editor if they have both Win32s and WinG installed on their system.
Warcraft II Strategy: Basics The editor included with Warcraft II allows Windows 95/98/NT and Macintosh users to create their own scenarios by editing the map, units, and even sound effects.