Based on this tutorial: https://fast-dds.docs.eprosima.com/en/latest/fastdds/getting_started/simple_app/simple_app.html
It demonstrates a realtime publisher / subscriber application.
Fast CDR
apt install libfastcdr-dev
Fast RTPS
apt install libfastrtps-dev
Fast DDS tools
apt install fastddsgen fastdds-tools
cmake .
make
Open a terminal and type
./DDSHelloWorldPublisher
Open another terminal and type
./DDSHelloWorldSubscriber