MDI Apps
You now have the tools and skills in place to begin to work with MDI Stage 1 Apps, where an app is a single R Shiny web application for interactive data analysis.
High-level view of app configuration
The MDI apps framework is itself an R Shiny app. When the web page is first loaded, it calls Shiny with sufficient information to load the UI with a launcher interface ready to support data upload and/or app selection.
A specific MDI app is a set of instructions for how to populate that initial framework with an integrated set of tabs and widgets toward some purpose in interactive data analysis.
Page filling with an app does not replace the framework, it adds to it. As a result, when you write an MDI app you will not care about the typical app-level UI and server functions - the framework does that for you. You will spend your effort writing code for the specific tools you wish to add to your pages, mostly by constructing appStep modules and widget modules. You can see why it is important that you understand the R and Shiny : Modules section above.