I am using one of the SS templates (design_template). I've changed the names of the links (left hand side) changed the colors and activated use hover. When checking the preview it's not working . I obviously must do something wrong (as usual) but don't know what.

The links in that template are title objects -- effectively images. As such, you don't have hover or underline which apply only to text objects.

So if you want a hover color, change the link objects to be text objects.

Thanks Bruceee, it works beautifully.