How can i make a GUI for my battery life?

Ive made this script where i have a flashlight with battery life, and the lower it gets the lower the intensity gets so it gets weaker and weaker. Do you have any good idea on how to make a GUI texture in the corner, like a bar that follows and gets lower as the batterylife drain?

Dont really know if this is necessary but heres some code for ya:

#pragma strict
 
//Variables START
 
//Light Source && Battery Life
var flashlightLightSource : Light;
var lightOn : boolean = false;
var lightDrain : float = 0.01;
var batteryLife : float = 0.0;
var maxBatteryLife : float = 2.0;
 
//Variables END
 
function Start()
{
        batteryLife = maxBatteryLife;
        flashlightLightSource = GetComponent(Light);
}
 
function Update()
{
        if(lightOn && batteryLife >= 0)
        {
                batteryLife -= Time.deltaTime * lightDrain;
        }
       
        flashlightLightSource.light.intensity = batteryLife;
       
        if(batteryLife <= 0)
        {
                batteryLife = 0;
                lightOn = false;
        }
       
        if(Input.GetKeyDown("n"))
        {
                toggleFlashlight();
               	
               
                if(lightOn)
                {
                        lightOn = false;
                }
                else if(!lightOn && batteryLife >= 0)
                {
                        lightOn = true;
                }
        }
}
 
function toggleFlashlight()
{
        if(lightOn)
        {
                flashlightLightSource.enabled = false;
        }
        else
        {
                flashlightLightSource.enabled = true;
        }
}

Same thing as a Health Bar. Look for soem tutorials on that.
For example: