That's just a tool to write the ISO file to USB, it may download the file but if not get the ISO from the button on the same page that says "Get Installation Media". I don't get the same page you'll see (I have different Windows), going from memory.
Run the ISO maker/installer and skip "install", select 'make USB installer" - then use the downloaded ISO file and the tool will do the rest.
Insert that USB stick into the PC you're installing Windows on and set the BIOS to boot from USB. Follow the instructions on screen once the install begins.