MijoVideos is easily installed as any Joomla component. That should be done through your site's backend.
Once you log in, you should open the Extensions => Install/Unistall section and click on the [Browse..] button in the Upload Package File section. Navigate to the same MijoVideos file you have downloaded earlier and select it. Then click on the [Upload File & Install] button to start the installation. It will install :
1. The main MijoVideos component
2. Front-end categories, channels, playlists, videos and modules
3. Language files
4. Database tables (#__mijovideos_categories, #__mijovideos_channels, #__mijovideos_fields, #__mijovideos_files, #__mijovideos_likes, #__mijovideos_playlists, #__mijovideos_playlist_videos, #__mijovideos_processes, #__mijovideos_process_type, #__mijovideos_reports, #__mijovideos_report_reasons, #__mijovideos_subscriptions, #__mijovideos_videos, #__mijovideos_video_categories)