Run this by calling:
docker run -p 8888:8888 simonbiggs/geant4-examples
Then type either
localhost:8888 (linux) or
192.168.59.103:8888 (windows or mac) into a chrome or firefox browser.
If you have any trouble getting this to work first try running
docker pull simonbiggs/geant4-examples just in case I have released an update fixing your problem. If you are still having trouble then feel free to contact me I am more than happy to help.