diff --git a/README.md b/README.md
index b44866b..deaf7ef 100644
--- a/README.md
+++ b/README.md
@@ -58,6 +58,43 @@ The following regions and their corresponding counties are predefined in the fun
 - **New York City**: New York, Bronx, Queens, Kings, Richmond
 - **Long Island**: Nassau, Suffolk
 
+---
+### How to Calculate a Field in ArcGIS Pro Using Python
+
+To use the `get_region_by_county` function for calculating a field in **ArcGIS Pro**, follow these steps:
+
+#### Step 1: Prepare Your Data
+Make sure your dataset contains a field with county names. For this example, we'll assume there is a field called `County_Name` that contains the county name for each feature.
+
+#### Step 2: Open the Field Calculator
+1. In **ArcGIS Pro**, open your project and the relevant map or scene.
+2. Right-click the layer that contains the data you want to update.
+3. Click on **Attribute Table** to view the features.
+4. Right-click the header of the field where you want to store the region names (e.g., `Region`).
+5. Select **Field Calculator** to open the calculation dialog.
+
+#### Step 3: Enter the Python Expression
+In the **Field Calculator** dialog, do the following:
+
+1. Ensure that the **Parser** is set to **Python**.
+2. In the **Expression** box, type the following code:
+
+    ```python
+    get_region_by_county(!County_Name!)
+    ```
+
+    - The exclamation marks (`!County_Name!`) reference the `County_Name` field in your dataset.
+    - The function `get_region_by_county` will be applied to each row to calculate the corresponding region.
+
+#### Step 4: Implement the Python Code
+To ensure the function is available in the field calculator, follow these steps:
+
+1. In the **Field Calculator**, click the **Show Code Block** checkbox.
+2. In the **Pre-Logic Script Code** box, paste the function definition for `get_region_by_county`:
+
+#### Step 5: Apply the Calculation
+- Click **OK** in the **Field Calculator** to run the function. The `Region` field will be populated with the corresponding region for each feature based on the `County_Name` field.
+
 ---
 
 ### Installation
@@ -74,4 +111,5 @@ The following regions and their corresponding counties are predefined in the fun
 
 ### License
 
-This project is licensed under the GPL License - see the [LICENSE](LICENSE) file for details.
\ No newline at end of file
+This project is licensed under the GPL License - see the [LICENSE](LICENSE) file for details.
+