Plug your iPad into your PC or Mac, open iTunes, in the left hand column you will see your iPad listed under Devices, click on your iPad there. On the window that opens you will see your iPad and info about it, and some tabs across the top of that window, click the MUSIC tab, check the Sync Music box and check "Entire music library" if you want everything to sync to your iPad. You should now see the music that you downloaded on your iPad. If not, go back to the left hand column and under the "Library" heading click on the Music icon, your music library will open up and show you all the songs you have downloaded, they should have a check next to each song you have downloaded, if not check each box and re-sync to iPad.