I am trying to access my music on Itunes. i can see the list of my music and still not able to access it - why?

Difficult to say with no information. Are you using a PC or Mac (what OS is on the computer) ? Your iTunes is up-to-date ? Are you getting any error messages ? What have you tried to see if it fixes whatever the problem is ? Are you using, as the page that you posted from suggests, iTunes in the Cloud or iTunes Match ?