update documentation

README.md

@@ -29,8 +29,26 @@ This overwrites the default implementation of generate_schema_name from the core
 ```
 
 #### smart_source
-This macro helps use keep a check on the bigquery costs and at the same time validate sql queries end to end
-You can use the codegen package to have the script generated and then replace `source` with `smart_source`
+This macro helps use keep a check on the bigquery costs and at the same time validate sql queries end to end.
+You can use the codegen package to have the script generated and then replace `source` with `smart_source`.
+[Link](https://github.com/dbt-labs/dbt-codegen#usage-1) on usage of codegen for generating SQL for a base model
+
+Snippets to generate base mode code for reference
+
+Executing using scratchpad
+```
+{{ codegen.generate_base_model(
+    source_name='<source_name>',
+    table_name='<table_name>'
+) }}
+```
+
+Execting the macro as an operation
+```
+dbt run-operation generate_base_model --args '{"source_name": "<source_name>", "table_name": "<table_name>"}'
+```
+
+On the generated sql, replace `source` with `smart_source`
 
 ```sql
 with source as (