MiwoVideos is easily installed as any WordPress plugin. That should be done through your site's backend.
Once you log in, you should open the Plugins => Add New => Upload section and click on the [Browse..] button in the Upload Package File section. Navigate to the same MiwoVideos file you have downloaded earlier and select it. Then click on the [Install Now] button to start the installation. It will install :
1. The main MiwoVideos plugin
2. Front-end categories, channels, playlists, videos and modules
3. Language files
4. Database tables (#__miwovideos_categories, #__miwovideos_channels, #__miwovideos_fields, #__miwovideos_files, #__miwovideos_likes, #__miwovideos_playlists, #__miwovideos_playlist_videos, #__miwovideos_processes, #__miwovideos_process_type, #__miwovideos_reports, #__miwovideos_report_reasons, #__miwovideos_subscriptions, #__miwovideos_videos, #__miwovideos_video_categories)