docs/osbuild.1: extend EXAMPLES section

This extends the EXAMPLES section with more examples, reduces their
complexity, and also restructures the layout to make it nicer to read
in the resulting TROFF file.

docs/osbuild.1.rst

@@ -120,16 +120,40 @@ The above pipeline has no base and produces a qcow2 image.
 EXAMPLES
 ========
 
- 1. To build a basic qcow2 image of Fedora 30, use:
+The following sub-sections contain examples on running **osbuild**. Generally,
+**osbuild** must be run with superuser privileges, since this is required to
+create file-system images.
 
-    ``sudo osbuild --sources samples/sources.json samples/base-qcow2.json``
+Example 1: Run an empty pipeline
+--------------------------------
 
-    Superuser privileges are needed to mount file systems, create loop devices,
-    and setup isolation environments.
+To verify your **osbuild** setup, you can run it on an empty pipeline which
+produces no output:
 
- 2. To run **osbuild** from a local checkout, use:
+    |
+    | # echo {} | osbuild -
+    |
 
-    ``sudo python3 -m osbuild --libdir . --sources samples/sources.json samples/base-qcow2.json``
+Example 1: Build a Fedora 30 qcow2 image
+----------------------------------------
 
-    This will make sure to execute the `osbuild` module from the current
-    directory, as well as use it to search for stages, assemblers, and more.
+To build a basic qcow2 image of Fedora 30, use:
+
+    |
+    | # osbuild ./samples/base-qcow2.json
+    |
+
+The pipeline definition ``./samples/base-rpm-qcow2.json`` is provided in the
+upstream source repository of **osbuild**.
+
+Example 2: Run from a local checkout
+------------------------------------
+
+To run **osbuild** from a local checkout, use:
+
+    |
+    | # python3 -m osbuild --libdir . samples/base-rpm-qcow2.json
+    |
+
+This will make sure to execute the **osbuild** module from the current
+directory, as well as use it to search for stages, assemblers, and more.