How to make a Minecraft resource pack/texture pack?

I don't know how to extract all the files or even put them together to make a texture pack. I get that you need some kind of photo editor and I have that, I just don't know how to get the files or to put them into a pack. I'm just looking to change textures for the most part.

Something to do with going into the texture pack folder and editing the textures to your liking. I'm sure there's a tutorial out there somewhere, good luck!