DOC: Add section clarifying parentheses vs. brackets usage

Author: disneysandhya1

doc/source/getting_started/index.rst

@@ -669,3 +669,5 @@ material is enlisted in the community contributed :ref:`communitytutorials`.
     intro_tutorials/index
     comparison/index
     tutorials
+    parentheses_vs_brackets
+

doc/source/getting_started/parentheses_vs_brackets.rst

@@ -0,0 +1,41 @@
+Parentheses vs. Brackets in pandas
+==================================
+
+In pandas, beginners often get confused between **parentheses `()`** and **square brackets `[]`**.  
+Understanding the difference is essential for using pandas effectively.
+
+**Parentheses `()`** are used to **call functions or methods**:
+
+.. code-block:: python
+
+    import pandas as pd
+    df = pd.DataFrame({'A': [1, 2, 3], 'B': [4, 5, 6]})
+
+    # Call the head() method to see first 5 rows
+    df.head()
+
+**Square brackets `[]`** are used to **access data or select columns**:
+
+.. code-block:: python
+
+    # Select a single column as a Series
+    df['A']
+
+    # Select multiple columns as a DataFrame
+    df[['A', 'B']]
+
+**Key points:**
+
+- `()` always executes something (a function/method).  
+- `[]` always retrieves data (like indexing or slicing).  
+- Mixing them up is a common source of errors for new pandas users.
+
+**Additional examples:**
+
+.. code-block:: python
+
+    # Using brackets to filter rows
+    df[df['A'] > 1]
+
+    # Using parentheses to chain method calls
+    df[['A', 'B']].head()