You will need a basic understanding of Fluentd before you attempt to run it on Kubernetes and ofcource a Kubernetes Cluster ready.
Fluentd and Kubernetes have a bunch of moving parts.
The most important components to understand is the fluentd tail plugin.
This plugin is used to read logs from containers and pods on the file system and collect them.

I would highly recommend to use manifests from the official fluentd github repo for production usage

The manifests found here are purely for demo purpose.
The manifests in this repo are broken down and simplified for educational purpose.