In the support section under Help with Windows Store is the following thing to try when installation is failing:
Replace USER_Name
Download the game and wait for it to error.
Replace USER_NAME with your local PC Username.
Go to c:\Users\User_name\AppData\Local\PackagesMicrosoft.WindowsStore_8wekyb3d8bbwe\LocalCache and delete all the files in there.
Reboot your PC.
Attempt the download once more.
My question is, where do I replace user_name? What is the context? Is this for my PC user account, my MS Store account, or something else?