Help my little bro with MC textures?

To draw transparent parts on texture.png… You just need a paint program that handles transparent pngs. Most do. I know GIMP does, and Photoshop, obviously.

To draw a transparent part on a transparent png, you usually use the eraser tool in the paint program, usually looks like one of those big old chunky erasers, or the eraser on a pencil. You should make sure that the pixels you want to be transparent are in fact 100% transparent, I'm not sure what happens when you give it a partially transparent png, but I can guarantee you it won't come out right. An easy way to ensure 100% transparency is to turn the 'strength' of the eraser tool to 100% in the paint program. And all your paintbrushes should be at 100% strength, too.

Erase any colors that you want to leave blank. Including white.