Changing gear knob

Where is this How-to guide to be found? all i can see is how to dismantle a gear knob... which i don't want to do.
I've posted on the A2OC how it's possible to just change the knob. It took a bit of thought and some small part has to be do this It is a separate part, however, and so can be replaced. I'm sure that a search of the forum would find what I've just talked about..