extend package build info

BUILD.rst

@@ -14,6 +14,10 @@ The IMOS passive audio tools library is wrapped in a python package named IMOSPA
       python3 -m pip install --upgrade pip
       python3 -m pip install --upgrade build
 
+   .. ::
+   
+#. Build and install the package locally
+
    .. code-block::
   
       # test build & local install
@@ -33,6 +37,8 @@ The IMOS passive audio tools library is wrapped in a python package named IMOSPA
       python3 -m pip -v uninstall IMOSPATools
       python3 -m pip -v cache purge
 
+#. Makefile
+
    There is also a simple `Makefile <Makefile>`_ that is capable of the generic make functionality:
 
    .. code-block::
@@ -43,6 +49,8 @@ The IMOS passive audio tools library is wrapped in a python package named IMOSPA
 
    .. ::
 
+#.Usage
+
    To use the functions from the package, just import the module and call the functions:
 
    .. code-block::