Hello Fran,
your 'parts' are called 'Division'. Normaly there are 18 of them: Intro 1-4, Variation 1-4, Ending 1-4, Fill Up 1-3, Fill Down 1-3. You can program 3 Modes per Division: major, minor and 7th.

Read Page 178 of your G70 OM:
The G-70 allows you to program 54 different patterns
per Style, some of which can be selected via
dedicated buttons (MAIN [1]~[4], etc.). Some Patterns
are selected on the basis of the chords you play in the
chord recognition area of the keyboard (major,
minor, seventh).

Greeting
Peter