You can show a specific topic programmatically by using the ShowTopic method.

Create a CheckedChanged event handler for CheckBox1 and add code so it looks like the following:

To write code in Visual Basic

Private Sub CheckBox1_CheckedChanged(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles CheckBox1.CheckedChanged
      C1DynamicHelp1.ShowTopic("WordDocuments/glossaryofterms.htm")
End Sub

To write code in C#

private void checkBox1_CheckedChanged(object sender, System.EventArgs e) 
{ 
    c1DynamicHelp1.ShowTopic("WordDocuments/glossaryofterms.htm"); 
}