How to sync various studio flashes?

I just bought a studio flash kit. I have a wireless radio trigger which works for one flash fine, but how to I get it to work on another flash simultaneously? It came with sync cords but they do not fit in my camera. I have a Nikon D90.

Most studio flash kits are mono lights. Once one of the lights fire the other lights slave off of it. I would assume the kit you bought would do this, too.