Open Mod Organizer 2
Click the Downloads tab
Click the gear icon or right-click in the downloads area
Select Add Manual Download
Browse to the downloaded archive file
Select the file and confirm
Wait for the file to appear in the Downloads list
Double-click the download to install it
Or right-click the download and select Install
If needed, drag and drop the archive file directly into the Downloads tab
If the file does not appear, verify it is a supported archive format such as ZIP, 7Z, or RAR