If you want to make use of platys-generated stack without the internet, then you can use the following steps.
Generate a stack on a machine with Internet access as documented in Getting Started with platys and modern-data-platform stack. You don't have to start the stack, just generate the artefacts.
Now pull the images from the docker registry by using
docker-compose pull
One all the images are downloaded, you can export them intot an archive file
docker save -o docker-images.tar $(docker-compose config | awk '{if ($1 == "image:") print $2;}')
Now copy the archive as well as the generated artefacts to the machine without internet and load the images into the local docker registry
docker load -i docker-images.tar
Set the DOCKER_HOST_IP and PUBLIC_IP environment variables and start the stack using
docker-compose up -d