Seeking comprehensive tutorial on creating flashable zips

I have googled this for days, and I cannot seem to find a solution.

I want to find a tutorial to create a flashable zip (for both CWM and TWRP), and I am looking for something that will describe the components, the Edify script, and anything else. I am somewhat familiar with this, but can't seem to create my own.

NOTE: I do not want to use a template, or any other "starting zip". If I want to add files or components to system (fonts, boot animation, or some other mod), I want to learn how to do it from scratch: as if all I have is 7-zip, a suitable text editor, and that is it.

I have modified zip files before by extracting/editing a document, and then re-zipping, but I never have just extracted the whole file and then re-zipped it and had it work successfully.

If I have to use a device specific binary, then I need to know where to find this.

I have been working/flashing zip files for 4 years and am frustrated that I always have to use some "automated tool" or someone's zip template to start with.

I appreciate any help in advance!

Syntropic