< Can someone pls show me an example?

In the Prop. Sheet set:
grid.MemberClass to "mycol"
grid.MemberClassLibrary to "fullpathToMemberclasses.prg"

Memberclasses.prg:

****************************************************************
* Put any #INCLUDE statement here.

****************************************************************
DEFINE CLASS myCol as Column
****************************************************************
Name = "myCol"
FontName = "Verdana"
FontSize = 8
HeaderClass = "myHdr"
* You can not leave this blank:
HeaderClassLibrary = "fullpathToMemberclasses.prg"

ENDDEFINE && myCol
****************************************************************

****************************************************************
DEFINE CLASS myHdr as Header
****************************************************************
Name = "myHdr"
FontName = "Verdana"
FontSize = 8
FontBold = .T.

ENDDEFINE && myHdr
****************************************************************