As it´s name Genesis Supersuit suggests, the supersuit is only for Genesis. Which means it will not work on your Gen 3 or Gen 4 figures. You will have to install the free DAZ Studio 4.5 with Genesis figure. Genesis comes with basic male, basic female and basic child shapes. You can use the supersuit on them.
Genesis is the newest figure and it is able to use clothes made for Gen 3 and Gen 4 figures via Autofit. Only shoes are a problem. It can also use Gen 4 skins (but not Gen 3 skins). If you want to use characters made for V4, M4 etc., you have to buy the GenX plugin which converts them to Genesis.
Genesis can be turned into many different shapes - man, woman, child, gorilla, troll etc. All can wear the same clothing - either clothing made specificaly for Genesis, or that for older figures via autofit. Figures based on Genesis are called Gen 5 - so far there is Victoria 5, Michael 5, Stephanie 5, Hiro 5 and Teens 5, also several other non-millenium shapes like Hitomi, Sadie & Sam, Mavka, Jasmin, Jason, Amy, Mr. Hyde etc., and also some monsters.