This tutorial should help you get started with simulating robot navigation in a predefined environment. We will also have other mooving objects in the enviroment that the robot can track. This tutorial assumes some familiarity ROS (i.e. setting up a workspace etc.) and commands are provided for Ubuntu 20.04 (ROS noetic). For other distrbutions simply replace noetic with whatever your distro corresponds to e.g. melodic for Ubuntu 18.04.
The first step is to have the full installation of ROS by running:
$ sudo apt install ros-noetic-desktop-full
This will install - among other things - ROS and Gazebo. Gazebo gives provides a configurable environment to simulate the robot navigation. You can confirm the installation of gazebo by running:
$ gazebo