wpmu DEV dashboard installation

I click the download link and it goes to my download folder and Unzips it as a folder in my downloads. The add plugin's on WP requires a zip format. I then right clicked and saved the link file (keeping .zipped) but then when I try to use the WP plugin uploader it give the report

The package could not be installed. PCLZIP_ERR_BAD_FORMAT (-10) : Unable to find End of Central Dir Record signature