Yamaha QY100 Owner's Manual page 85

Step Accompaniment Recording
Style Number and Section
Any preset style number from 001 through 128, the "end
pattern" (number 129), or any user style number from U1 through
U64 can be entered for each measure. The style name appears to
the right of the style number. Only one style & pattern (section)
can be entered per measure, and that pattern will begin playing
from the beginning of the measure at which it is entered.
A pattern entered once will continue to play until a different
pattern is entered. If you want to change sections without chang-
ing the style number, only the section need be entered. Playback
will stop automatically when an "end pattern" (style number 129)
or an ending section is encountered.
In the example display below the intro pattern (section) of
style 001 plays for the first measure, then the main A pattern
(section) of the same style is selected in measure 2.
Style number/name
Section
85