edited data dictionary description

docs/data_dictionaries/ferc1_db.rst

@@ -1,5 +1,5 @@
 ===============================================================================
-FERC Form 1 Data Dictionary
+Raw FERC Form 1 Data Dictionary
 ===============================================================================
 
 We have mapped the Visual FoxPro DBF files to their corresponding FERC Form 1

docs/data_dictionaries/index.rst

@@ -3,20 +3,40 @@
 Data Dictionaries
 =================
 
+Data Processed & Cleaned by PUDL
+^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+The PUDL data dictionary provides detailed metadata for the tables
+in the PUDL database. This includes table descriptions,
+field names, field, descriptions, and field datatypes.
+
 .. toctree::
-   :caption: Data Processed & Cleaned by PUDL
    :maxdepth: 1
+   :titlesonly:
 
    pudl_db
 
+Raw, Unprocessed Data
+^^^^^^^^^^^^^^^^^^^^^
+Certain raw datasets (e.g. FERC Form 1) require additional effort to process.
+We load these raw sources into SQLite databases before feeding them into
+the PUDL data pipeline. The dictionaries below provide key metadata on
+these raw sources including table name, table
+description, links to corresponding database tables,
+raw file names, page numbers, and data reporting frequency.
+
 .. toctree::
-   :caption: Raw, Unprocessed Data
    :maxdepth: 1
+   :titlesonly:
 
    ferc1_db
 
+Code Descriptions & Metadata
+^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+This section contains mappings of codes in the raw tables to their
+corresponding labels and descriptions in the processed PUDL database tables.
+
 .. toctree::
-   :caption: Code Descriptions & Metadata
    :maxdepth: 1
+   :titlesonly:
 
    codes_and_labels