Best documentation would be official documentation: http://docs.openstack.org/kilo/install-guide/install/apt/content/ch_preface.html (http://docs.openstack.org/kilo/instal...)

for openstack networking, best documentation: https://www.rdoproject.org/networking/networking-in-too-much-detail/ (https://www.rdoproject.org/networking...)

Rest get your hands dirty in openstack to understand it better.