Hi Tracy,
Welcome to YamahaSynth. The best way to learn the MOXF is to learn to use the terminology of the instrument. This way when answers are supplied you know where to look and you’ll begin to understand the concepts.

By “layered sounds” you probably mean in “Performance Mode”. Using the term “Performance” makes clear where in the MOXF architecture we are discussing... and it will help us communicate about what to do.

A Performance is a set of parameters that are applied to the “Voice” you associate with it. A Performance has four slots, called Parts; you can associate the set of Part parameters with any MOXF Voice. These parameters “offset” the original Voice programming, specifically for this combination. This allows for non-destructive editing. You can change the tuning or the area on the keyboard where something will sound, without permanently changing the original Voice data. This allows the same “Full Concert Grand” to be used Split at C3 and lowered an octave in one Performance and split at F#2 and raised up an octave in another Performance. Part parameters are offsets. Offset parameters leave the original data in tact.

Among the Part parameters are the NOTE LIMIT (Low Note—High Note) and NOTE SHIFT (semitones offset of the tuning).

From the [PERFORMANCE] main screen
Press [EDIT]
Press [1] to view Part 1 parameters
Press [F1] VOICE
Press [SF3] LIMIT
Here you can set the Low and High Note Limits for the Part. Yamaha uses the convention where middle “C” is C3.
C-2 is the lowest Midi Note; G8 is the highest Midi Note.
An acoustic piano is A-1 thru C7

Press [F4] TONE
Press [SF1] TUNE
Here you can offset how the tone generator responds to a Note-On event in semitones. +/-12 is an octave.

Each Part [1]~[4] has these settings.

Knowing the mode (Performance), and the area (Part), you’ll be better prepared on figuring out *where* in Edit you need to be looking.
Hope that helps.