Look for Frozen Throne.exe or Warcraft III.exe in the folder where you installed the game.
Most older installers provide . These are the "classic" versions best for offline play and custom maps. If you are looking to play online via official servers (Battle.net), you will likely need to use the modern Warcraft III: Reforged launcher through Blizzard. warcraft-iii-tft-apun-kagames-exe
Install it to a simple directory like C:\Games\Warcraft III . Avoid C:\Program Files as Windows permissions there can sometimes cause "Unable to write to disk" errors for older games. Look for Frozen Throne