Added detailed explanation

Author: Murilo Marinho

docs/installation.md

@@ -13,3 +13,28 @@ sudo add-apt-repository ppa:dqrobotics-dev/development
 sudo apt-get update
 sudo apt-get install libdqrobotics libdqrobotics-interface-json11 libdqrobotics-interface-coppeliasim libdqrobotics-interface-coppeliasim-zmq
 ```
+
+## Installation details
+
+We begin by setting up sources. This wll tell `apt` where to find the debian packages. They are currently being deployed
+in GitHub.
+
+```commandline
+curl -s --compressed "https://smartarmstack.github.io/smart_arm_stack_ROS2/KEY.gpg" \
+| gpg --dearmor \
+| sudo tee /etc/apt/trusted.gpg.d/smartarmstack_lgpl.gpg >/dev/null
+sudo curl -s --compressed -o /etc/apt/sources.list.d/smartarmstack_lgpl.list \
+"https://smartarmstack.github.io/smart_arm_stack_ROS2/smartarmstack_lgpl.list"
+```
+
+We then update `apt` once to get the new information, as shown below.
+
+```commandline
+sudo apt update
+```
+
+Lastly, we install all available packages.
+
+```commandline
+sudo apt-get install ros-jazzy-sas-*
+```