I guess nobody wants to write you a book lesson.
Keeping it simple; ie CloneDVD usage without theory:
If your original DVD is a SL release (4.37GB or less) then choose DVD5 in CloneDVD and burn to a SL media. You will get a copy with no compression necessary.
If your original DVD is a DL release (4.37GB or more) and you still want to burn it to a SL media, choose DVD5 and CloneDVD will automatically transcode/compress the data to fit on your SL media. Remove whatever elements you don’t want in order to lower compression levels and raise quality a bit. Then just keep clicking on the “Next” button and your will progress to the Rip and then the Burn phases of making a backup.
If your original DVD is a DL release (4.37GB or more) and you want to split it over two SL media in order to avoid loss of quality due to compression then keep CloneDVD set to DVD5, [I]highlight the main-movie titleset [/I] and then click on the “Scissors Icon” to enter CloneDVD’s splitting interface. Move the sliders to include the main-movie chapters you want split over the two disks. It is a two step manual procedure … first make backup disk1 then go back and make backup disk2 to include all that was not included on disk1. Manually juggle the extras anyway you want over the two disks. … if you desire, you can still eliminate extras, audio tracks, or elements which you don’t want or need on your backup. Watch the compression meter during your split maneuvers to be sure you are retaining 100% quality on both backup disks.
If your original DVD is a DL release (4.37GB or more) and you want to burn it to DL backup media (Verbatim brand [I][U]strongly[/U][/I] suggested), then choose DL in CloneDVD and your will get an uncompressed DL backup.
… Or use Slysoft’s CloneCD to make an actual 1:1 mirror duplicate (retaining the original’s layer break) onto DL media. Suggest you use only Verbatim brand (made in Singapore) DL media. No one else is capable of manufacturing reliable DL media at this point in time.