(a) create the technical framework, re-using as much as possible existing mechanism (like robot.txt, robot metadata tags, ...)
(b) communicate to the industry and create awareness to use this protocol
(c) create a governance framework to manage the protocol in the future.
It's an interesting initiative to follow because it provides publishers a tool to expose more high value content in a managed way. So far, the major public search engine didn't show big enthusiasm to participate but I guess it's more a wait and see position than a pure rejection. Having in mind all the pending case they are facing, ACAP might bridge the gap of copyrighting interpretation between Publisher and search engine. The status details of the mid term conference are on the-acap.org.