Declare a Magento theme (theme.xml)
Register the theme in the Magento system: the registration.php file
The notion of Vendor and Theme
Configure the theme images: the etc / directory and the view.xml file
The tree structure of theme folders (web, css, js, fonts, images)
Declare and add a logo (layout / default.xml)
Layout compositions, layout overload

Declare a module (namespace and module name)
Register the module in the Magento system: registration.php
Activate a module
Declaration of the router
The MVC model
Create controllers and actions
Customize the urls of the module
Add views (.phtml) and blocks