How to use conkeyref feature.

Dear all,

I am finding little bit hard to understand the keydef, conref and conkeyref features to use.  Presently I have refered the following link to understand the featureshttp://dita.xml.org/resource/keyref-overview-dita-12

Could any body help me to understand more on these features. It would be more helpful if I get some examples to understand this.

Thank you,

Rajesh