Connect your iPad to your computer using the USB cable that came along. In Windows it will be detected as Digital Camera and in fact the arrangement of folders which you will see in that is similar to most of the handycams and digicams.
Launch iTunes and you will see your iPad getting detected with an eject button next to it. Dont press it, just not yet.
Click on your iPad under Devices in iTunes. What you will see on the right hand screen are the details about your iPad and Storage Capacity details at the bottom of that. The storage details are nicely detailed with colours to help you know what is occupying your data more.
Copying Music / Videos to iPad :
Click on the Music Tab. Select Sync Music. It might warn you that all existing music on your iPad will be replaced by songs in your library. If this is the first time dont worry much, say yes.
Next you need to make choice either to copy entire music collection or only selected Artists, Albums, Genres or PlayList ( Now you know why I asked you create or import one )
Once you are done, click on the Sync Button and it will take all the music to your iPad. Revert to cancel. Similar procedure applies to Video and Movies.
Hope it helps