retrofit kit with motion and contact sensors?

I have a working alarm system in my home, with several zones. I would like to move to the Ring alarm system, and I understand a retrofit kit would allow me to using my current wiring. Does anyone know if I need would still need to purchase mulitiple contact sensors, range extendor, and motion detectors? I understand I would need to purchase a keypad, but do I need a standard Ring package if I'm using my current wired system with the retrofit kit? Thank you