Need help on changing Alpha depending on character's life

Hi, It's my first time learning Unity. I've been following a youtube channel tutorials so far, and I wanted to do something specific that is not included in the video.

I want to decrease my character's Alpha(transparency) depending on how much life my character has left.
ex) Full = 100%, one life left= 50%, no life left=2%, etc.
I have googled this for hours but I can't figure out which commands to use...

1. I'm not sure whether I should make a new script, or add onto an existing script that I already wrote in order to add multiple lives to my character.

2. I have no idea which code to use.

This is the youtube tutorial I've followed (I skipped some episodes as I didn't feel the need to include enemy health, projectiles, etc.):

 

If anyone needs to see my codes, I can attach some.
Just let me know which one!

 

You character is a 2D Sprite I assume, and you are programming in C#?

SpriteRenderer renderer = GetComponent<SpriteRenderer>();
renderer.color = new Color(0.5f, 0.5f, 0.5f, 1f); // This is RGBA (So the A is your alpha, or Opacity)

 

If I remember in the above example don't change the first three parameters of.0.5 should be 1, as this will change the colour was well you could use a math.min (30, value) this will allow for you to see the character just a bit if it dips below 30 health assuming your using 100 as full health that is, or if you go too low you will not see the character at all.

 

You have picked a good tutorial, I bought a while back his udemy version, his code is a bit sharp but it gets the job done.

 

Yes, I am using 2d sprite for my character in c#.
So, which script would I put this in? I have a script for managing my life count and I tried putting the code inside the update {} and it didn't work..
Or..do I make a new script and just put this code alone?
would I need to define anything using "public void " or something like that?

 

You count down script needs change the players colour alpha