dude i don't know how much more you need for a tutorial. you add tarpontech's code to your functions.php as you would for any php modification.
function go_vertical( $args ) {
$args[ 'menu_class' ] = 'sf-menu sf-vertical';
return $args;
}
add_filter( 'thematic_nav_menu_args', 'go_vertical' );
now your menu ul element will have the class "sf-menu sf-vertical". you don't need the other part any more as it is covered by thematic now.
you can find a sample vertical CSS at the superfish site:
http://users.tpg.com.au/j_birch/plugins/superfish/#sample3
i don't feel like trying it out, but as far as i can tell this is the CSS you need to add below the existing menu CSS:
/*** adding sf-vertical in addition to sf-menu creates a vertical menu ***/
.sf-vertical, .sf-vertical li {
width: 10em;
}
/* this lacks ul at the start of the selector, so the styles from the main CSS file override it where needed */
.sf-vertical li:hover ul,
.sf-vertical li.sfHover ul {
left: 10em; /* match ul width */
top: 0;
}
/*** alter arrow directions ***/
.sf-vertical .sf-sub-indicator { background-position: -10px 0; } /* IE6 gets solid image only */
.sf-vertical a > .sf-sub-indicator { background-position: 0 0; } /* use translucent arrow for modern browsers*/
/* hover arrow direction for modern browsers*/
.sf-vertical a:focus > .sf-sub-indicator,
.sf-vertical a:hover > .sf-sub-indicator,
.sf-vertical a:active > .sf-sub-indicator,
.sf-vertical li:hover > a > .sf-sub-indicator,
.sf-vertical li.sfHover > a > .sf-sub-indicator {
background-position: -10px 0; /* arrow hovers for modern browsers*/
}