preface vs show someone the ropes

preface

• To give a preface to. 

• To introduce or make a comment before (the main point). 

• An introduction, or series of preliminary remarks. 

• A title or epithet. 

• The beginning or introductory portion that comes before the main text of a document or book. 

• The prelude or introduction to the canon of the Mass. 

show someone the ropes

• To explain the fundamentals of something to someone.