You can deploy the code from Github repository either through PaaSHQ Management Console or Command line client.
Below are the links given for the both.
For PaaSHQ Management Console:
http://app42paas.shephertz.com/dev-center/working-with-apphq/#deployAppUrl
For Command line client:
http://app42paas.shephertz.com/dev-center/working-with-command-line-interface/#deploy
In case of deploying from Github, Either the provided Git repository must be public or if you want to deploy from private repository, you need to provide the pull permission to App42PaaS Github user.