diff --git a/README.md b/README.md
index 27dbf6b..07e8094 100644
--- a/README.md
+++ b/README.md
@@ -31,8 +31,7 @@ This goal of this project is to help you get better at Angular and NgRx by resol
 <a href="./apps/pipe-easy/README.md"><img src="https://img.shields.io/badge/8-simple pure pipe-green" alt="pipe easy"/></a>
 <a href="./apps/pipe-intermediate/README.md"><img src="https://img.shields.io/badge/9-wrapFn pipe-orange" alt="wrapFn pipe"/></a>
 <a href="./apps/pipe-hard/README.md"><img src="https://img.shields.io/badge/10-utilities pipe-red" alt="utilities pipe"/></a>
-
-<!-- <a href="./apps/scroll-cd/README.md"><img src="https://img.shields.io/badge/12-change detection -- scroll-orange" alt="change detection with scroll event"/></a> -->
+<a href="./apps/scroll-cd/README.md"><img src="https://img.shields.io/badge/12-change detection -- scroll-orange" alt="change detection with scroll event"/></a>
 
 </br>
 <img src="https://img.shields.io/badge/RxJs--gray?logo=rxjs" alt="RxJs"/>
diff --git a/apps/scroll-cd/README.md b/apps/scroll-cd/README.md
index f5e089f..807c7c8 100644
--- a/apps/scroll-cd/README.md
+++ b/apps/scroll-cd/README.md
@@ -4,12 +4,14 @@
 
 ### Information
 
-This challenge will teach you how to avoid unnecessary change detection cycles.
+In this challenge, you will need to optimize the change detection cycles run by Angular.
 
 Zone.js will trigger a change detection cycle each time a scroll event is dispatched. However we only want to show or hide a button at a specific scroll position. Therefore, we only want to refresh our application once.
 
 > You can vizualise how many times CD is triggered by installing the [Angular chrome devTool](https://chrome.google.com/webstore/detail/angular-devtools/ienfalfjdbdpebioblfackkekamfmbnh) and starting a new recording on the profiler tab.
 
+The following video will explain what is the goal of this challenge.
+
 ### Statement
 
 Your goal for this challenge is to avoid all those unnecessary change detection cycle and trigger a CD only when needed.