I'll hopefully clear a few things up for you.
There are a few different ways of writing information to a CD-RW. Programs like InCD and DirectCD use a method called packet writing, this allows you to use the CD-RW like a floppy disk.
Software such as Nero, can write to the CD in sessions, which are like tracks on an audio CD. The disadvantage with this is that as you add sessions/tracks to the CD-RW the CD-RW fills up and you end up with no space left on the CD-RW, you are not able to delete sessions that have already been burned onto the CD-RW. When you get to the end of a CD-RW, you have filled the CD with files in different sessions, you have to Finalise the CD-RW. This makes the CD readable all CD players.
This is probably the best, most reliable, way that you can burn files onto a CD or CD-RW.
You will be able to write information using Nero without InCD, it is a good idea to use only one CD writing software on you computer to avoid incompatabilities between them, just write the CD in sessions until the CD is filled up and then finalise the CD. You will still be able to erase a CD-RW after you have finalised it so you can start again.