installoption Q

i have some question about installoption
i can make one exe file with installoption (with INI)
and i want this.
click linktext -> write registry key
how can i this?
i am pretty rookie...please help me

Use the InstallOptions NOTIFY flag and a leave function. Then you will be informed when the user has clicked the link.

i don't understand...;-(
please descript easy
i am rooke very