Some tweaks to Python and e2e benchmarking docs (#4249)

diff --git a/docs/developing_iree/e2e_benchmarking.md b/docs/developing_iree/e2e_benchmarking.md
index 55450c8..d25ea4f 100644
--- a/docs/developing_iree/e2e_benchmarking.md
+++ b/docs/developing_iree/e2e_benchmarking.md
@@ -21,14 +21,27 @@
 ## 1. Run IREE's E2E TensorFlow tests to generate the benchmarking artifacts
 
 ```shell
-# Continuing from the "Running Python Tests" section of the doc linked above:
-$ cd ../iree-build/
+# Continuing from the "Running Python Tests" section of the doc linked above.
+# We need not only Python bindings, but also the TensorFlow compiler frontend.
+# Self-contained commands from that doc --- skip that if you have already
+# completed a build with Python bindings AND TensorFlow compiler frontend.
+$ cd iree-build/  # Make and cd into some build directory
+$ cmake ../iree -G Ninja \
+    -DCMAKE_C_COMPILER=clang \
+    -DCMAKE_CXX_COMPILER=clang++ \
+    -DIREE_BUILD_PYTHON_BINDINGS=ON  \
+    -DIREE_BUILD_TENSORFLOW_COMPILER=ON
+$ cmake --build .
+# Also from the Python get-started doc, set this environment variable:
+$ export PYTHONPATH=$(pwd)/bindings/python
 ```
 
 ```shell
 # --target_backends: All tests allow you to specify one or more backends to generate benchmarking artifacts for.
 # --artifacts_dir: The default location for these artifacts is under /tmp/iree/modules
-$ python ../iree/integrations/tensorflow/e2e/matrix_ops_static.py \
+# This is a Python 3 program. On some systems, such as Debian derivatives,
+# use 'python3' instead of 'python'.
+$ python ../iree/integrations/tensorflow/e2e/matrix_ops_static_test.py \
     --target_backends=iree_vmla
 # View the generated artifacts:
 $ tree /tmp/iree/modules/MatrixOpsStaticModule/
diff --git a/docs/get_started/getting_started_python.md b/docs/get_started/getting_started_python.md
index 14edbc2..aa8050d 100644
--- a/docs/get_started/getting_started_python.md
+++ b/docs/get_started/getting_started_python.md
@@ -62,22 +62,33 @@
 
 ## Building
 
+From the *parent* directory of the IREE git repository clone, create and enter
+a build directory, such as:
+
+```shell
+$ mkdir iree-build
+$ cd iree-build
+```
+
+Then build like this:
+
 ```shell
 # Also include -DIREE_BUILD_TENSORFLOW_COMPILER=ON if you want the TF compiler.
-$ cmake -G Ninja -B ../iree-build/ \
+$ cmake ../iree -G Ninja \
     -DCMAKE_C_COMPILER=clang \
     -DCMAKE_CXX_COMPILER=clang++ \
     -DIREE_BUILD_PYTHON_BINDINGS=ON  .
-$ cd ../iree-build/
-$ ninja
+$ cmake --build .
 ```
 
 ## Running Python Tests
 
+We continue to assume that we are in the build directory where we made the
+build in the previous section.
+
 To run tests for core Python bindings built with CMake:
 
 ```shell
-$ cd ../iree-build/
 $ ctest -L bindings/python
 ```
 
@@ -85,12 +96,13 @@
 comparison tests:
 
 ```shell
-$ cd ../iree-build/
 # TODO: Revisit once more patches land.
 $ ctest -L integrations/tensorflow/e2e
 
 # Or run individually as:
-$ export PYTHONPATH=../iree-build/bindings/python
+$ export PYTHONPATH=$(pwd)/bindings/python
+# This is a Python 3 program. On some systems, such as Debian derivatives,
+# use 'python3' instead of 'python'.
 $ python ../iree/integrations/tensorflow/e2e/simple_arithmetic_test.py \
     --target_backends=iree_vmla --artifacts_dir=/tmp/artifacts
 ```
@@ -109,6 +121,7 @@
 To install into your (hopefully isolated) virtual env:
 
 ```shell
+# See the above note about python3, and the above step setting PYTHONPATH.
 python bindings/python/setup.py install
 ```