If you want to find out more about Dianetics and Scientology, the best way to do this is to read an L. Ron Hubbard book on the subject. I personally recommend you read The Scientology Handbook.
This book really helped me with introducing people to exactly what Scientology is all about. It gives them things they can do and use straight away, and it answers the questions to the most puzzling parts of a person's life in easily understood language.