iPad storage
iPad Mini, iOS 9.3.1
If you have a 16GB iPad, then your storage is pretty much gone. The 16GB device only has about 12.5-13GB available storage out of the box.
Yep you will need to manage storage on your iPad, try tu delete all the apps you don't use on a daily basic,
follow the steps described here Check your storage on your iPhone, iPad, and iPod touch - Apple Support
The remaining space may be taken by cached temporary data. Try the following:
Settings > Safari > Clear History and Website Data
Force quit all apps
Restart, holding Sleep and Home buttons until the Apple appears
iPad storage