RS1 and RS2 should be 0.5 Ohm resistors rated at least 3 Watts, preferably 5 Watts.
Vref should NOT be connected to 5V! The voltage on the Vref pin sets the motor current per this formula: Stepper motor current (Amps) = Vref(volts) * 2.
For example, to set the motor current to 1.0 Amps per phase, the voltage applied to Vref should be 0.5 Volts.
The Vref voltage is usually derived by using a resistor divider from the 5V. Using a potentiometer in the resistor divider lets you adjust the Vref voltage.