The Help section says I can erase and reuse a CD-RW, but doesn't say how and I can't find anywhere how to do it. Thank you.
Use the Disk Utility in the /Applications/Utilities/ folder.
Where is that located? You're talking to a complete computer illiterate.
Choose Utilities from the Finder's Go menu. If that isn't an option, choose Applications and then double-click Utilities.
The 2nd suggestion did the job. A bit confusing though, not you, me. Not sure if I'll be able to do it again because I only guessed that I should click the disc insignia of the two choices. Thank you.
Retrieving data ...