Update the sample project to reflect current usage and have explanatory files in them

sample/sampleNovel/data_b/a8a28a246524_main.nwd

@@ -1,5 +1,7 @@
 ## Interlude
 
+% Notice that this is a file with the flag ‘N.Un’. The ‘N’ means it’s a novel file, and the ‘Un’ means it’s an unnumbered chapter. Unnumbered chapters can be treated separately from numbered chapters during export. Perfect for when you want to add an interlude, or for a prologue or epilogue.
+
 I am the very model of a modern Major-General  
 I've information vegetable, animal, and mineral  
 I know the kings of England, and I quote the fights historical  
@@ -13,3 +15,5 @@ With many cheerful facts about the square of the hypotenuse
 	With many cheerful facts about the square of the hypotenuse  
 	With many cheerful facts about the square of the hypotenuse  
 	With many cheerful facts about the square of the hypotepotenuse
+
+% Notice that the lines in the verse have highlighted spaces at the end of each line. (If the syntax theme allows it.) These are two spaces, which indicates that you want a hard line break at that point. The blank lines still indicate a paragraph. Press Ctrl+R to see what this renders like.

sample/sampleNovel/data_b/c0cbd2a407f3_main.nwd

@@ -3,6 +3,16 @@
 @pov: John
 @location: Earth
 
-This is the second scene in out story. We have no idea what’s going on, so we’re just going to ramble on until we have a few lines of text so that the editor has something to work with.
+Adding more scenes to a chapter is as easy as adding more scene files, with a level three heading, or just adding another level three heading in the same file if that works for the way you want to structure your files.
+
+In fact, if you wish, you can add all the scenes in the chapter file too. All novelWriter cares about is the level of the headings.
+
+### More Scenes
+
+@pov: Jane
+@location: Earth
+
+This is a second scene in the same file as the previous scene. You can always split the files up later.
+
+
 
-In fact, this scene is supposed to be about John, but we don’t really know anything about John, except that he is somewhere in space. Perhaps he’s lost? Or has gone where no man has gone before? Where is Jane then?