Ok, that makes a bit more sense. It's showing that of the 16 GB of internal storage that your tablet comes with, only 10.6 GB is available to the user (the other 5.4 GB are taken up by the OS and by preinstalled bloatware). Of that 10.6 GB, 3.32 GB are taken up by apps (including app data), and 5.92 GB are taken up by media files (photos, videos, music). These aren't necessarily files that you manually downloaded -- it might be cached data from your Google Photos or Google Play Music app, for example. 1.29 GB of that 5.92 GB of media is listed as "Downloaded," suggesting that you had downloaded at least some of it from the web.
Check the Download directory to see if you have a lot of media files there. Also, open your various media apps (like Google Play Music, YouTube, etc.) and look in their settings for an option to clear the cache. You can also go to Settings>Apps, select those apps, and clear the cache there as well. You can also clear data, but this will remove your account from the app as well -- you can always log back in, but any data from the app you might have saved would be wiped out.