Hello forum, I am hoping you could guide in the right direction

What have I done:
1. Started with the Ubuntu Mini.iso 20.04 I have basically created a custom build in a VM environment
2. I have installed xfce4 as the the Desktop engine.
3. I have installed Nemo and set it as the Preferred FileManager.
4. I have customized the theming and xfce panel layout.


What I want to do:
I want to create a LIVECD .iso so I can give it to others to install in our environment. Just like you would if you download Ubuntu 20.04, basically I want to create my own customized distribution.


What have I read and tried:
I went through this tutorial:
https://help.ubuntu.com/community/Li...ionFromScratch
It did work and I got a bootable .iso


What is the problem:
I don't understand why all my changes I made to the host machine are not in the Live environment or install.
I made the above changes .... but when I went through the tutorial and created the .iso I booted it up and its just the default XFCE desktop.
So, I went further and ran through the installation of the newly created .iso, and none of my changes of the host are there.
I am not really sure what I am missing.

My question is.....is that the correct set of procedures to follow? or is there another tutorial I should be reading.


Please I do not want to use, cubic, pinguyos builder, clonezilla or an thing like that, my goal is to build and understand this process myself, but It is very hard to find clear documentation on what to do.

Thank you very much in advance