Move content out of nested directory

The nested directory structure didn't seem to work well. Just use a 2
prefix for part two content.

book/src/pages/2-explore/loading.md

@@ -0,0 +1,7 @@
+# Loading Data
+
+Acquiring data, and transforming it into a workable state, can be one of the most time consuming parts of data analysis. In a later chapter we'll look at this process in more detail, but right now we're going to take a short-cut. If you're using the [project template][template], as described in the introduction, the data is already available and ready to go.
+
+Open up the file `Explore.scala`
+
+[template]: https://github.com/creativescala/creative-scala-data-template

book/src/pages/directory.conf

@@ -16,5 +16,6 @@ laika.navigationOrder = [
   cycles
   part-one-conclusions.md
   part-two-introduction.md
-  part-two
+  2-explore
+  2-loading-data
 ]

book/src/pages/part-two-introduction.md

@@ -18,7 +18,6 @@ which I think leads to a clearer understanding of these topics (particularly if
 
 ## Setup
 
-To work through this part of the book use a new project.
-Download the [creative-scala-data-template][template] from Github.
+To work through this part of the book, use the [creative-scala-data-template][template] from Github.
 
 [template]: https://github.com/creativescala/creative-scala-data-template