How to use Extension Installer

I am new to opencart and I am trying to develop some modules. I understand how to create a module, for example: in admin folder we need to create file controller/module.php, language/English/module.php, and so on. Currently I am developing a module by creating all files needed in each folders in my project one by one. In opencart 2 there is a feature called Extension Installer which I think is used to upload a module from outside the project, but I can't find the documentation to use it.
- How is the folder structure and files I need to prepare to upload a zip file to Extension Installer?
- How if I want to upload an xml file?
- Where can I find a documentation about module development using Extenstion Installer?

Any help is very appreciated. Thank you