The studio module allows you to use the existing feature of Odoo for creating your
own custom applications. You can use the fields, components, buttons, reports, etc.
from an existing application to build a new app. So, with lots of customizations
that Odoo provides, the app created will be completely different from what is existing.
You can use even the workflow and dependencies of existing modules.
For example, if you want to create an advanced sales module that requires some of
the functionalities in the Odoo sales module and certain additional features, you
can modify the Sales app using Odoo studio. You can add more fields, buttons, and
menus or you can change views.
You can create new models for your application by clicking on the new model button
on the menu bar on top. Then you can choose the features you need to use features
for a new model from the wizard.