Should have buttons both sides of the wheel, on/off on the right hand side, reset and +/- on the left hand.
When driving at your desired speed press the on button then the +, you can then take your foot off the accel pedal. To gain speed + to lower -, to disable you can lightly touch the brake pedal or press off.
You can accelerate as normal with the cruise on and it will go back to your set speed when you take your foot off.
Reset will use your last set speed only if the cruise is on.
Hope this makes sense, it worked for me today.