Issues building docker image

General
1

Im having trouble understanding how to proceed after puling a docker file from a repo
I have installed docker on ubuntu 20. and pulled from mediagis/nominatim
My goal is to run " docker build -t nominatim . "
as per instructions https://hub.docker.com/r/mediagis/nominatim , but when I do, I get the following error

unable to prepare context: unable to evaluate symlinks in Dockerfile path: lstat /home/james/Dockerfile: no such file or directory

I also cant seem to locate the docker file

in /var/lib/docker I have the following folders
{builder containers network plugins swarm trust
buildkit image overlay2 runtimes tmp volumes}

typing ‘docker images’ in the console reveals the image "mediagis/nominatim latest 687be9f4eccb "

Overlay2, which appears to be my driver, contains a multitude of files , none of which seem to correlate to 687be9f4eccb
The only place I have found this is in var/lib/docker/image/overlay2/imagedb/content/sha256 ( is this the docker file ?) if I navigate to this directory and try to run I get the same error message
unable to prepare context: unable to evaluate symlinks in Dockerfile path: lstat /var/lib/docker/image/overlay2/imagedb/content/sha256/Dockerfile: no such file or directory

Could someone tell me where I am meant to run this build command from ?

2

If you pull an image from Dockerhub it’s already there and you don’t have to build anything. These instructions describe how to build the image if you cloned the Github repo. Maybe this is what you should do because the content on Dockerhub is outdated.