In this pages, David Baker Consulting published valuable peace of knowledge to explain the clauses of ISO9001:2015 clause by clause in a simple way.
They started with general provision of the new standard and what are the main changes.
The Standard is available in ISO website here ISO 9001:2015
ISO 9001:2015 Sections & Clauses
Section 2: Normative references
Section 3: Terms and definitions
Section 4: Context of the organization
Section 9: Performance evaluation
They added case studies for further orientation.