On Setup the VM you can find everything to setup the prebuilt VM-image. This can be used for developing and offline usage. Alternatively you can take a look at Setup a Docker container where you can find instruction on how to use the docker container. If you want to use the VM or container for developing purpose, you should take a look at Developing after reading either the page about setting up the VM or Docker.
The page about Manual Setup is mostly for documentation purpose – it is strongly recommended to use the prebuilt VM-image or the Docker container.