scecil4735

I am a new user of v6. I can't seem to get my project to back up to a disc. I feel I am missing something obvious... but after repeatedly going over the 'help' instructions continue to come to a standstill. Please explain the process to a person who obviously isn't very computer savvy. When I get to step 4 the option boxes , including 'span disc', are not highlighted and will not let me select 'span disc' ..... Please help????????