If the voltage is too low for the ESC spec (how many cells are you using?), you will not get it to arm and run.

Assuming you have the correct number of cells for the ESC and motor, your receiver must be powered up. If you are running more than 3S, most ESCs cannot adequately run the receiver through the throttle connection, and you will need to have a separate BEC powering the receiver; in that case you may also need to disconnect the middle wire of the throttle connection from ESC to receiver. The manual for your ESC should cover all this.

If you need further help, let me know details of the ESC, motor and battery, and I will try to give a simpler point of view...Chris