Fix links and minor corrections

Signed-off-by: Physic69 <vencutsub11111111111@gmail.com>

Author: Physic69

get_started.md

@@ -8,28 +8,29 @@ simulation using Gazebo.
 ## Step 1: Install
 
 :::{important}
-If you are a [ROS](https://ros.org) user, please first read our tutorial on [ROS/Gazebo installation](ros_installation)
+If you are a [ROS](https://ros.org) user, please first read our tutorial on [ROS/Gazebo installation](https://github.com/gazebosim/docs/blob/master/ros_installation.md)
 :::
 
 The recommended installation for new users is the use of binary
 packages available for the platform to use:
 
 |Platform|Gazebo Versions|
 |---|---|
-| Ubuntu 24.04 Noble | [Gazebo Harmonic](/docs/harmonic/install_ubuntu){.external} (recommended), (recommended if using ROS 2 Jazzy) and [Gazebo Ionic](/docs/ionic/install_ubuntu){.external}
-| Ubuntu 22.04 Jammy | [Gazebo Harmonic](/docs/harmonic/install_ubuntu){.external} (recommended) and [Gazebo Fortress](/docs/fortress/install_ubuntu){.external} (recommended if using ROS 2 Humble)
-| Mac Ventura | [Gazebo Harmonic](/docs/harmonic/install_osx){.external} (recommended) and [Gazebo Fortress](/docs/fortress/install_osx){.external}
-| Mac Monterey | [Gazebo Harmonic](/docs/harmonic/install_osx){.external} (recommended) and [Gazebo Fortress](/docs/fortress/install_osx){.external}
+| Ubuntu 24.04 Noble | [Gazebo Jetty](/jetty/install_ubuntu.md){.external} (recommended), [Gazebo Harmonic](/harmonic/install_ubuntu.md){.external} (recommended if using ROS 2 Jazzy) and [Gazebo Ionic](/ionic/install_ubuntu.md){.external}
+| Ubuntu 22.04 Jammy | [Gazebo Harmonic](/harmonic/install_ubuntu.md){.external} (recommended) and [Gazebo Fortress](/fortress/install_ubuntu.md){.external} (recommended if using ROS 2 Humble)
+| Mac Ventura | [Gazebo Harmonic](/harmonic/install_osx.md){.external} (recommended) and [Gazebo Fortress](/fortress/install_osx.md){.external}
+| Mac Monterey | [Gazebo Harmonic](/harmonic/install_osx.md){.external} (recommended) and [Gazebo Fortress](/fortress/install_osx.md){.external}
 | Windows | Support via Conda-Forge is not fully functional, as there are known runtime issues [see this issue for details](https://github.com/gazebosim/gz-sim/issues/168).
 
 If the desired platform is not listed above or if a particular feature in a
-given [Gazebo release](releases) is needed,
+given [Gazebo release](https://github.com/gazebosim/gz-sim/releases) is needed,
 there is an installation package per release available with all the
 installation options:
 
-* [Gazebo Ionic installation](/docs/ionic/install){.external} options (EOL 2026 Sep)
-* [Gazebo Harmonic (LTS) installation](/docs/harmonic/install){.external} options (EOL 2028 Sep)
-* [Gazebo Fortress (LTS) installation](/docs/fortress/install){.external} options (EOL 2026 Sep)
+* [Gazebo Jetty installation](/jetty/install.md){.external} options (Expected: EOL 2030 Sep)
+* [Gazebo Ionic installation](/ionic/install.md){.external} options (EOL 2026 Sep)
+* [Gazebo Harmonic (LTS) installation](/harmonic/install.md){.external} options (EOL 2028 Sep)
+* [Gazebo Fortress (LTS) installation](/fortress/install.md){.external} options (EOL 2026 Sep)
 
 ## Step 2: Run
 
@@ -45,7 +46,7 @@ gz sim shapes.sdf  # Fortress uses "ign gazebo" instead of "gz sim"
 ```
 
 This command will launch both the Sim server and Sim GUI with a world
-that contains three simple shapes.
+that contains six simple shapes.
 
 Add the `-v 4` command line argument to generate error, warning,
 informational, and debugging messages on the console.
@@ -92,10 +93,10 @@ custom SDF file.
 ## Step 4: Explore and learn
 
 This tutorial has covered the basics of getting started with Gazebo.
-There are more [versioned tutorials](/docs/citadel/tutorials){.external}
+There are more [versioned tutorials](/citadel/tutorials){.external}
 covering the basics of the GUI, creating worlds and robots, and more.
 
-Each [Gazebo library](/libs){.external} also has a set of tutorials and
+Each [Gazebo library](https://gazebosim.org/libs/){.external} also has a set of tutorials and
 examples. Explore these resources, and don't forget to ask questions and
 find solutions at [answers.gazebosim.org](http://answers.gazebosim.org).