Hi. Yes, you need to have the FoxySpider button on your toolbar before starting to use the add-on. In the new release (0.52), the button is added automatically after installation, so you don't have to be a Firefox savvy to add it. In the recent releases there are many addition to the add-on, including bigger control over the appearance of the gallery, broken link detector and more.
Installation page is here.
Additinoally, I would like to inform that a FoxySpider page on Face book has been launched recently. In that page there are announcements about new releases, FAQ section and more.