As this is the first concept to be introduced please start by watching the first 1m29s of this video giving an introduction to the overall concept of column chromatography:
Introduction to Column Chromatography
The overall principle of ion exchange chromatography is outlined in this video:
The Principle of Ion Exchange Chromatography - Video
or this:
The Principle of Ion Exchange Chronomatography - Animated
To get working knowledge of the chromatography concepts associated with protein purification a series of handbooks are available from GE Healthcare Life Sciences.
To get working knowledge of ion exchange chromatography please read and digest the following chapters in the handbook on the topic.
Chapters to read and digest:
Chapter 1, chapter 3 Separose Fast Flow (starting on page 82), chapter 3 Source (starting on page 66).