Begin game play, then press [F3] to display the practice menu. Remove all pins, then resume the game. Intentionally throw gutter balls in each frame to have the game score them as strikes.
Throw ball over gutter
Either clear all the pins or leave some. Roll a gutter ball. While the ball is still in the gutter, right click and click "Practice Menu", then "OK". Then, throw a gutter ball and it will go over the gutter.