first of all load from one disk, but save to another, then you will not lose any original information.

yes page 3 saves only the sequencer, this is correct. You can then load this on page 3 to any of the 10 song positions in the sequencer.

if you use only presets all you need is the sequencer file, you do not need any other files.

once you have collected 10 songs in the sequencer, then you do a page 1 save to save all 10 at the same time.

if you use composers and sound edits, just make sure the correct composer and sound files are saved at the same time as the page 1 sequencer save.

so use page 3 save only to get an existing song in single song format.

use page 3 load to arrange single songs as you want them in order in the sequencer.

then use a page 1 save to save all 10 songs in the sequencer at one time - in combination with any other sections of the keyboard you need for the songs to play correctly.