Hello!
We just wanted to let you know that if you pre-purchased Warcraft III: Reforged, you are able to install and play classic Warcraft III. To do so, please use following installers:
After starting the game for the first time (after installation), you will see two options. You can choose to enter your Classic CD keys or log into your Battle.net account that has pre-purchased Warcraft III Reforged.