At the moment, you can’t install addons for World of Warcraft: Classic using the Twitch addon installer, and even the curse website will have some bugs you need to iron out when using. So I wrote up this handy guide for Windows 10. If it’s different for iOS, please chip in!
Step 1: Find the addon from a reliable publisher. When in doubt, use Curse. It’s reliable and virus free. Install the addon!
Step 2: Find the file location. You may notice that after installing the addon it won’t actually affect the game client. That’s because you installed a ZIP file which the program can’t read.
To find the zip file on your computer, open your file manager, go to
World of Warcraft -> classic -> Interface -> AddOns . You will find the ZIP file with the same name as the addon you want to install.
Step 3: Extract the files. Do this by right clicking the ZIP file and selecting the option ‘extract all.’ Your computer will ask where you want to place the extracted files. Select, again,
World of Warcraft -> classic -> Interface -> AddOns.
Step 4: Jump in! At this point, your game client will be able to read the program files and run the AddOn. This is how it worked for me, and I hope this will spare you some time.