The simplest way is to open Windows Explorer and type this into the address bar at the top:
%appdata%
When you press Enter, it will take you to the correct folder.
The AppData folder is a hidden folder, so usually you won't see it in the lists. You could go to the Tools > Folder Options > View dialog and change the option to show hidden files and folders, but that's not recommended unless you know enough not to make a mess of your computer.
One other thing: How did you decide to put this question into a forum about Word? It's really a Windows thing...