Once the image download is complete, double click the .iso file to mount it.

It should appear in the sidebar of your File Explorer as a DVD drive. Make note of the Drive letter your computer assigns it. In this example it is the E: Drive.

Reopen, or return to your command line window. Type DISM /Online /Cleanup-Image /RestoreHealth /Source:E:\Sources\install.wim and press enter. Substitute the source drive letter here for what Windows has assigned the drive on your computer.

Wait for the command to finish. It will indicate if it failed.