Question about the support article re: Microsoft Store "Replace USER_Name" - Where?

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?

You replace nothing. You need to delete the files under your Win10 profile. Your personal profile name is the name of the folder you need to select.