To think the it was controlling 120v AC before, i don't like having mains on my breadboard, and that to control a DC-motor, ah well
Skip the breadboard, just solder it up, you are going to need that.
Use a transistor to drive the relay, put a flyback diode and hook it up like this.
Or you can just get one of the 2-relay units the sell online, and hook the switching pins as shown.