It should be noted that I went to the tutorial, thinking that I was doing something wrong in the first place.
I can not associate a data source to a new text box in a new app or an existing app, so I thought for sure I must be doing something wrong, but in following the exact steps of the tutorial, it appears to be a bug because what works in the tutorial doesn't work now !!!!!
Your image helped a lot. I mis-understood the tutorial. My mistake is thinking that once I've clicked on a text box or an image in the app, I thought I should be able to associate a data source in the right hand pane.
The step that I missed, is clicking on that top icon in the right hand pane to associate data.
I see now, that the tutorial clearly has a red box around that top icon, and it is totally me that missed that additional step.
However, that said. It would be far more intuitive to show the DataSource or having the ability to add or change a data source in the menu bar after clicking on any item in the app.
It is not obvious to click on the top icon in content ofthe right had pane to add or change the DataSource !!!