Just download the media tool to your computer.
Press enter on the tool.
wait until you here what do you want to do on this computer.
update this computer is already highlighted, tab to the next button and
press enter.
you will get a message saying, downloading windows 10, you can keep using
your computer.
When it is downloaded, follow the steps it gives you.
You do not fool with any mounting or any thing like that.
just install after following the different screens.