Open the ConstraintLayout that was auto-generated when we created the project. It is probably already in a tab at the top of the editor. If not, it will be in the res/layout folder. Its name is activity_main.xml.
Inspect the XML in the Text tab and note that it is empty, apart from a TextView that says Hello World. Switch back to the Design tab, left-click the TextView to select it, and tap the Delete key to get rid of it.
Now we can build ourselves a simple, yet intricate, UI. ConstraintLayout is very useful when you want to position parts of your UI very precisely and/or relative to the other parts.
To get started, look in the Widgets category of the palette and find the CalenderView. Drag and drop the CalenderView near the top and horizontally central. As you drag the CalenderView around, notice that it jumps/snaps to certain locations.
Also notice the subtle visual cues that show when the view is aligned. I have highlighted...