Fix development doc (#837)

* Fix dev doc
* Clarify BUILD.bazel location

DEVELOPMENT.md

@@ -15,24 +15,40 @@
 ## Running the Plugin
 
 1.  Clone [googleapis](https://github.com/googleapis/googleapis) and
-    [gapic-showcase](https://github.com/googleapis/gapic-showcase/) and install
-    protoc.
+    [gapic-showcase](https://github.com/googleapis/gapic-showcase/).
 
 2.  Copy the protos from Showcase into googleapis/google/showcase.
 
     ```sh
-    cp gapic-showcase/schema/google/showcase/v1beta1 googleapis/google/showcase/v1beta
+    mkdir googleapis/google/showcase
+    cp -r gapic-showcase/schema/google/showcase/v1beta1 googleapis/google/showcase/v1beta1
     ```
 
-3.  Add the new microgenerator rules to the protobuf directory's `BUILD.bazel`
-    file as follows:
+3.  Add the new microgenerator rules to
+    `googleapis/google/showcase/v1beta1/BUILD.bazel` file as follows:
 
     ```python
     load(
         "@com_google_googleapis_imports//:imports.bzl",
         # Existing rules here.
         "java_gapic_assembly_gradle_pkg",
         "java_gapic_library",
+        "java_proto_library",
+        "proto_library_with_info",
+    )
+
+    proto_library_with_info(
+        name = "showcase_proto_with_info",
+        deps = [
+            ":showcase_proto",
+        ],
+    )
+
+    java_proto_library(
+        name = "showcase_java_proto",
+        deps = [
+            "showcase_proto",
+        ],
     )
 
     # This should either replace the existing monolith target or have a unique name