You may enter a PGN number in these fields to indicate the Next or Previous PGCN to skip to. PgcEdit will warn you (by highlighting the field in pink) if you wish to enter a PGCN which is not contained within the current title or is out of range.
If there are no buttons, cell or post commands, having a Next PGCN is essential, or else the DVD will stop after the final cell of the PGC has finished playing.
You should not enter a Previous PGCN in the menu domain as this is not standards compliant. In this case, if you wish to return to another PGC, enter a PGC number in the GoUp link (and use the Return or GoUp button on your remote).
Entering a Next/Previous PGCN link equal to the current PGCN can be advantageous if you wish to quickly skip to the beginning or end of the PGC (see also Enable Navigation Buttons for a full explanation).