Take your foot off the pedal and press down the RES/+/SET/– switch when you reach the desired speed. The moment you release the switch, the set speed is fixed, and ACC with LSF begins.
When driving slower than about 25 mph (40 km/h):
If the vehicle is moving and the brake pedal is not depressed, pressing the switch fixes your set speed to about 25 mph (40 km/h) regardless of current vehicle speed. If your vehicle is stationary, you can set the vehicle speed even with the brake pedal depressed.