The corkboard just shows subdocuments of the currently selected folder/document in the binder. Be sure your second chapter is a folder on the same level as the first chapter folder and that it is selected in the binder.
As for format changing, this works the same as in any other text formatting app. Just select the text you want to change and change the formatting. Go to the Text menu to show the ruler (which has things like line spacing in it too) and call up the fonts panel etc. You can also set up default formatting in the Text Editing Preferences and apply these to documents using the Documents ? Convert menu.
I definitely recommend going through the tutorial - both the one that comes with the app and the screencast on the main product page - and having a browse through the Help file for these topics if you have not done so already.
All the best,