...
Magento Doc: Prepare Environment and basic business (4d)
...
Creating a Module (2h)
...
Create a database when installing module (5h)
...
Controller (4h)
...
Model/Resource Model/Collection (1d)
...
EAV and extension attributes (1d)
...
Layout (1d)
...
Event (4h)
...
Plugin/Rewrite (5h)
...
Service Contract/WebApi (1.5d)
...
Admin Customize: Menu/System/ Grid/Form/UiComponent (2d)
...
Another Technique (2d)
Cronjob, Command line: 1d
Knockout js: 1d