Main menu and child sub-menu

Hi – My website is alteregovoices.com

I have a menu option “Biography”.

What I really want is for this option to be clickable so as to display the sub-menu, but not to have to display a page.

Also, I would like it to be highlighted as a drop-down mwnu with an arrow.

I got this code from elsewhere, but not sure where to put it:

.nav-menu li > a:after {
color: #888;
content: ' ?';
}

.nav-menu li > a:hover:after {
color: #444;
content: ' ?';
}

.nav-menu li > a:only-child:after {
content: '';
}

or if the code is correct for raindrops.

Any help is always appreciated!