How do I make part of a material transparent?

Hello, I searched quite a while but didn’t find anything about how to make a certain color of a material transparent, I tried to understand with th M_HUD_Health_Bar material from the HUD example content but I can’t find out how to make just a color of the material transparent ;

4729-material.png

I would like to make the white color invisible but I can’t figure it out.
If you know how to do this please explain it or point me to useful tutorials maybe ?
Thank you for your help

White is very hard to mask, you should use some single color channel or just use texture with alpha. You could use math to detect when all channels are 1 or closer and set alpha on those points

The thing is that I am a programmer so I don’t understand how this works exactly, could you explain how you would do it inside the material editor please ?
Sorry about my lack of knowledge and thank you for replying so quickly

I’ve figured it out, I made another texture from the one I wanted to take the white away and turned the white into black, made the rest all white, imported it into the material editor and mutiplied my default mask with the Green part of the texture I just made and plugged it up to the opacity (Blend Mode : Translucent and Lighting Mode : Unlit)