For example:

Replace idmsetup.exe with the actual name of the IDM installer executable.

reg add "HKCU\Software\DownloadManager" /v "ShowTips" /t REG_DWORD /d 0 /f reg add "HKCU\Software\DownloadManager" /v "FirstRun" /t REG_DWORD /d 1 /f

Find the to disable the "Tips" popup on first launch. Set up a Group Policy to force the browser extension.