One command from an elevated PowerShell prompt. It fetches the signed installer, checks it's genuinely ours, and opens the setup wizard.
PS> $f="$env:TEMP\WatchMyTech-Setup.exe"; irm https://watchmytech.com/downloads/WatchMyTech-Setup.exe -OutFile $f; $s=Get-AuthenticodeSignature $f; if($s.Status -eq 'Valid' -and $s.SignerCertificate.Subject -like '*RECCEIT*'){Start-Process $f -Wait}else{Write-Error 'Signature check failed - aborting'}
Open PowerShell as Administrator — Start menu → type "PowerShell" → Run as administrator — then paste with Ctrl+V and press Enter.