If you are using a custom thesis class file provided by your department or school, then you should stick to the styles set up in that class. If not, you may need to change the default style of your chosen class to fit the requirements. Volume 1 described how to change the fonts used by chapter and section headings for the KOMA-Script classes. For example, if the chapter headings must be set in a large, bold, serif font you can do:
This can be redefined as required. For example, suppose you are required to have centred headings, then you can do:
This book is also available as A4 PDF or 12.8cm x 9.6cm PDF or paperback (ISBN 978-1-909440-02-9).