Microsoft does not distribute Windows ARM ISOs as far as I know. The basic procedure is to download some ESD files from Microsoft, then convert it into an ISO.
If you use Parallels, just let it create a Windows VM automatically. It will make an Windows ARM Home/Pro ISO in your Downloads Folder, and you can use that for a manual installation later.
Another easy option is to use CrystalFetch on macOS to build the ISOs.