1. Enter PowerShell mode
In order to mount the ISO, you need first type in PowerShell at the command prompt and then press enter.
2. Mount the ISO
You now need to run the command: Mount-DiskImage -ImagePath "C:\Installs\ExchangeServer2019-x64.iso"
3. Run the Install
Run the following command to Install Exchange 2019: .\Setup.EXE /Mode:Install /InstallWindowsComponents /IAcceptExchangeServerLicenseTerms /Roles:MB