diff --git a/README.md b/README.md
index 2e53a8c1e..04c56d87e 100644
--- a/README.md
+++ b/README.md
@@ -5,10 +5,20 @@ Warning: This is an experimental plugin that comes with no support, use it at yo
 
 This package contains a Mermaid feature for CKEditor 5.
 
+## CKEditor 5 Mermaid - Running manual test
+
+You can test all of the features of the `ckeditor5-mermaid` plugin with the manual test sample.
+
+After installing dependencies it's enough to execute the following script at the root of your local clone of the project:
+
+```
+yarn start
+```
+
 ## License
 
 See [LICENSE.md](LICENSE.md) file.
 
 ### Trademarks
 
-**CKEditor** is a trademark of [CKSource](https://cksource.com) Holding sp. z o.o. All other brand and product names are trademarks, registered trademarks or service marks of their respective holders.
\ No newline at end of file
+**CKEditor** is a trademark of [CKSource](https://cksource.com) Holding sp. z o.o. All other brand and product names are trademarks, registered trademarks or service marks of their respective holders.