why cant i see whats on my ipad ,when i conect it to my pc

You cannot directly access data/files on your iPad when connected to your PC. If not already installed on your PC, you will need to install the most recent version of iTunes for Windows:

Download and use iTunes for Windows – Apple Support

Once installed, you’ll be able selectively synchronise or transfer data between your PC and iPad. More information can be found here:

Use iTunes to sync your iPhone, iPad, or iPod with your computer - Apple Support

You would view music content and add music content in iTunes. Have you used that computer to sync your music in the past?