With the ISO file in a local folder, we now need to extract the file in order to run the Office installer. To do so, let's download the latest version of 7zip.
It is a very simple and light program. Once 7zip is downloaded and installed, right-click the ISO file, and go to 7-zip > Extract Here.
Access the new folder created after the ISO extraction, and double-click setup.exe to run the Office installer.
Let the program install and run. Enter the product key when required.