1. Ensure the game installed properly with no errors (verify integrity of game files)
2. Run the game (amrts.exe) out of the Army Men RTS folder (steamapps - common - Army Men RTS)
2. Run the game in administrator mode
3. Set compatibility mode to Windows 98/ME (on some computers it works in Windows 8 or 7 compatibility modes, however I strongly recommend Windows 98 compatibility as it never had launch issues)
4. Check screen resolution, 1280 x 1024 is the max resolution this game will run in without mods. (If your computer doesn't automatically adjust screen resolution this supposedly will interfere with the opening cutscene playing)
5. Update DirectX and Graphics Drivers

This is based on experiences using Windows 11, however this should work for Windows 10.

In order to remove the black screen to try running the game with different settings I had to restart the computer.

Running the game out of the folder instead of through steam doesn't add to steam in-game time totals

3DO support no longer exists, and the readme.txt troubleshoots Win95-XP systems and primarily focuses on DirectX issues you most likely won't have.

Hope this guide saves you the trouble and lets you enjoy this game as quickly as possible.
These solutions aren't perfect but should get the game running or at least point you in the right direction.