Simplify the following text for a Grade 8 native English-speaking person.
Original: PL does not have a holy book ( like a Bible ) , however , they have PL 21 Precepts and the PL 21 Principles which were revealed by the Founders of the Church .
Simplified: PL does not have a holy book , it has 21 PL Precepts which were announced by Tokuchika Miki on September 29 , 1947 .