It might help if you understand that “scratch pad” is a term used by computer programmers to refer to an area of memory that is used for temporary storage which has no permanent effect. It even has its own Wikipedia entry.

As the manual says (page 44):

One song is always active and worked on.

So if you have not created any chains or songs then you will automatically be working in the scratch pad.

Then as the manual continues:

The intended purpose of the scratch pad row is to enable experimentation with chains and patterns without affecting already programmed song rows.

No you can’t name chains. You name songs when you save them. Songs are made up of chains. To see all chains press Function + Song/Edit at the same time.
Everything I know about navigating around the Song screen I learned from the tutorial.

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