diff --git a/book/chapter-06-gbapp-reference.md b/book/chapter-06-gbapp-reference.md
index 7b76834b..496e0ef0 100644
--- a/book/chapter-06-gbapp-reference.md
+++ b/book/chapter-06-gbapp-reference.md
@@ -57,6 +57,10 @@ wget -q https://packages.microsoft.com/keys/microsoft.asc -O- | sudo apt-key add
 sudo add-apt-repository "deb [arch=amd64] https://packages.microsoft.com/repos/vscode stable main"
 sudo apt update
 sudo apt install code
+
+sudo apt-get install libxtst-dev
+apt-get install libpng-dev
+
 ```
 
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