Log into the official Blizzard Battle.net account management page. Go to the "Redeem a Code" section and enter your classic 26-character CD keys.
The path you take to download the game depends on whether you own the original CD keys or are buying it as a new player. 🚀 Option 1: You Already Own Classic CD Keys warcraft-3-the-frozen-throne-download
If you own the original physical keys for Reign of Chaos and The Frozen Throne , you do not need to purchase the game again. Log into the official Blizzard Battle