How do you add more files to a cdr

how do you add more files to a cdr once its already been burned?

is there a way where to do this?

If so which software?

I have nero 5 and clone cd 4

this is possible with nero but only if the last session of the cd-r is open…

How can I do the add files to a cd r and what do u mean it has to be open already

Start reading this: http://en.wikipedia.org/wiki/Optical_disc_authoring