The book "Enterprise Information Systems Engineering: The MERODE approach" describes the method. The book is available from Springer. KULeuven Students can order a personal copy at a discount price via KU Leuven's subscription to Springer (Use the EZ-proxy if accessing from outside the KU Leuven network). This book is also the main subject of the KU Leuven course D0I71A.
The BPMN YouTube playlist will provide you with an introduction to Business Process Modelling basics, and provide you with a tutorial on the modelling language BPMN
The BPMN Exercises page provides you with some exercises and solutions.
The edX MOOC on UML Class Diagrams for Software Engingeering will provide you with an introduction to UML class diagrams. You will learn how domain modelling helps to shape your business and acquire the basics for reading UML Class diagrams well.
The MERODE Slides and exercises are the material that I use to teach MERODE at KULeuven (course nr. D0I71A).