Switch on the power supply
Ensure the supply will be capable of providing the power to move the motor: some low current power supplies can overload when enabling the motor (and turn-off) which causes the drive to reset.
Ensure that the Safe Torque Off (STO) circuit is connected and powered as indicated in the manual. Otherwise, it will just not be possible to enable the motor.
Switch on the power supply and wait 10-15 seconds.