Set up the balls in the triangle ‘any which way’. It doesn’t matter. The White goes in its usual place and is hit to make the break. The winner is the player that pots the last ball on the table, leaving the ball that they struck still in play.
In Any Ball Pool any ball may be struck in an attempt to pot another ball; e.g. striking the Red to pot the White, a Red to pot a Red, the Black to pot a Red, and so on. It’s just about impossible to play safe or to snooker!