diff --git a/Practical/Assignment-4/IoT - Code-4.py b/Practical/Assignment-4/IoT - Code-4.py
index 9e6c41f..b5df6d7 100644
--- a/Practical/Assignment-4/IoT - Code-4.py	
+++ b/Practical/Assignment-4/IoT - Code-4.py	
@@ -6,6 +6,13 @@ Problem Statement: Temperature and humidity sensing using DHT11.
 Code from InternetOfThingsAndEmbeddedSystems (SPPU - Third Year - Computer Engineering - Content) repository on KSKA Git: https://git.kska.io/sppu-te-comp-content/InternetOfThingsAndEmbeddedSystems
 """
 
+# NOTE: PLEASE REFER DHT11 repo by notkshitij for initialization: https://git.kska.io/notkshitij/DHT11/
+
+# This code will only work in the virtual environment
+# To enable the virtual environment, change current working directory using 'cd <DIR>'
+# Activate the virtual environment using 'source bin/activate'
+# Run this code 'python3 IoT\ -\ Code-4.py'
+
 # BEGINNING OF CODE
 # NOTE: GPIO PIN 16 used
 
@@ -29,6 +36,8 @@ try:
       print("Humidity: %-3.1f %%" % result.humidity)
     else:
       print("Error: %d" % result.error_code)
+      # Error 1 implies sensor not detected, thus no data 
+      # Error 2 implies checksum error, data corrupted, i.e. GPIO connection might be lose
     time.sleep(3)
 except KeyboardInterrupt:
   print("Program stopped by user.")