If you are using the CLI, there is a tutorial on how to use most of the functionality of Octavia here:
If you are using the API directly, then the only action would be to include Octavia in your projects list (if it isn't already) and change your endpoint from neutron to octavia. The Octavia API is fully compatible with the Neutron-LBaaS v2 API spec.
If you are using the python client, you will need to switch to python-octaviaclient or to the openstack SDK, and I am unfortunately not aware of a guide to do that. However, it is a remarkably similar service (object model and API are 100% compatible), so making the transition should hopefully not be very difficult, and we are happy to help in #openstack-lbaas on IRC if you need specific assistance.
--Adam