Run the following command to setup dependencies required for the open manipulator
sudo apt-get install ros-melodic-ros-controllers ros-melodic-gazebo* ros-melodic-moveit* ros-melodic-industrial-core
Move inside the ROS workspace and clone open manipulator package
Assuming workspace name is 'robotics'
cd robotics/src
mkdir manipulator
cd manipulator
git clone https://github.com/ROBOTIS-GIT/DynamixelSDK.git
git clone https://github.com/ROBOTIS-GIT/dynamixel-workbench.git
git clone https://github.com/ROBOTIS-GIT/dynamixel-workbench-msgs.git
git clone https://github.com/ROBOTIS-GIT/open_manipulator.git
git clone https://github.com/ROBOTIS-GIT/open_manipulator_msgs.git
git clone https://github.com/ROBOTIS-GIT/open_manipulator_simulations.git
git clone https://github.com/ROBOTIS-GIT/robotis_manipulator.git
Move to workspace root and build the package
cd ..
catkin build
or
catkin_make