"5" clauses?
What are you talking about?
What "5" clauses and where did you get this?
Besides, ISO 9001 has been discussed hundreds of times already in the link you've been given.
Very likely he is referring to the five auditable sections of ISO 9001:2000, sections 4 thru 8.
A very short answer would be:
Section 4 General Requirements and Documentation Requirements.
Section 5 Management Responsibility
Section 6 Resource Management
Section 7 Product Realization
Section 8 Monitoring, Measuring and Analysis (mostly of the quality management system)
For better detail, the courses are two days, three days, or five days.
May I suggest that the starting point is to get a copy of the standard and reading it.