The Great Schools Partnership (greatschoolspartnership.org) and the League of Innovative Schools (LIS) member site at the New England Secondary Schools Consortium (lis.newenglandssc.org; username: lakeregionme; password: nessc1) have tons of resources available on every aspect of Proficiency Based Learning.
To better grasp the context, meaning, and implications of content area standards, there are any number of workshops and conferences devoted to disseminating and unpacking those standards. The standards websites listed above may contain links to those learning opportunities; so too will the websites and publications for the content area professional associations.
And, of course, many schools in Maine are doing this work. You can always check out the websites of other schools and districts in the area, and from the list of schools on the LIS website, for examples of how others have identified their standards and indicators.