A playfield forms the basic foundation of an Amiga display and determines
its fundamental characteristics.  To form a playfield, you program the
hardware registers of the custom chips with the basic parameters of the
type of display you want.  Forming a playfield involves selecting the
number of colors, setting up a color table and bitplanes, and selecting
the resolution and display mode.

To understand how Amiga playfields work, it will be helpful to review how
the Amiga's video displays are produced.

 how the amiga's video display is produced