I signed up for my own developer site yesterday, and tried it out today for the first time. And I must say, it is a nice and fluent way of creating apps for SharePoint!
Once you have the site and Napa all set up in your development environment, you will find the Napa tools in the Site Contents:
After launching the tools, you can create a new app project with a couple clikcs, and later on, you will find all your apps here, in the Napa Tools.
You can create both different types of Office apps and SharePoint Apps by clicking Add New Project.
The most simple way to create your app is to do it right in the browser! The default SharePoint app has several sample files to get you started:
The references between these files have already been made, so add your stuff an click Run Project:
and Napa takes care of packaging and installing, and uninstalling the old version when needed.
Just to get a small taste of how this thing works, I did a couple small customizations to the project, like
- adding some text, an iFrame to display the web part, an a button on the default page
- adding an editable paragraph in the web part
- and slightly changing the css style of the Web Part content and adding some styling for the button.
When this little demo is run, this is how it looks after clicking the button to display the Web Part:
If you want to, you can also open a copy of the project to VisualStudio for editing.