Let me quote from the lessons walkthrough
The UiDemo_Login.xaml file should start with a description. We can also use an
annotation in the very first activity, whether it’s a sequence or a flowchart, to mention the
function of each component and the use of the arguments. We typically add a
Precondition too, in case a particular screen needs to be active beforehand, for instance.
The “we can also use an annotation” bit makes me think that a Description is not the same thing as an Annotation. The “we typically add a Precondition” bit reinforces that idea.But I am not a native English speaker so I could be wrong here.
Anyway, having a description and a precondition text in an annotation is not a bad idea, but if it is only a text in an annotation I would expect to see something like
By convention, we use Annotations to describe the activity and document its preconditions and post conditions, if any. Right-click on the top activity and choose “Add annotation”. Now…