Contributing to MAAS code base (step-by-step tutorial)

Hello,

  I'd like to contribute to a code base of MAAS (actually have ~3 patches ready already), but I failed to find a step-by-step tutorial how to do the proper contribution. Is there a formal way described how to contribute a patch and what needs to be filled where?

  I'm quite familiar with GitHub (forking + PR process), but very new to LaunchPad and specifically MAAS project (which does not use Bazaar, but Git). I managed to checkout lp:maas repo using git clone (as per general LaunchPad instructions), but not sure how to push the changes back + how to request a PR-like patch review process.

Thank you in advance for any link / step-by-step explanation,
Roman Dolejsi