The content you choose to cover will, of course, be determined by your learning objectives. Here are my suggestions for the basic topics that you should consider covering if you want to give faculty a good grounding in open educational resources and prepare them to integrate them into their classes.
Getting Started
OER Definitions - What are OER; the 5 Rs
Why OER are important: advantages of and considerations for using OER in the classroom, including college affordability issues, problems with the textbook market, the potential of OER to address equity gaps and to create new possibilities in the classroom through open pedagogy
Copyright and Open Licenses
What is copyright? What are open licenses? What is the relationship between copyright and open licensing? What are the various open licenses and what do they allow / not allow?
Finding and Evaluating OER
Metasearches; using Google Advanced Search; using OER repositories
OER evaluation rubrics; sites that offer peer reviews
Creating OER
Tools, platforms, licensing
Open Educational Practices / Open Pedagogy
Definitions, examples, how can they be applied to improve learning in the classroom?
Many resources about OER exist which you can take advantage of when planning the content of your CoP. Videos, podcasts and readings can all be curated to form a basis of material from which faculty can learn. This is how I organized the first community of practice that I did, along with powerpoint presentations that I would deliver and then discuss with the group.
There are also complete texts on OER that can be used to structure your community of practice. In my second community of practice, I used one such text, the OER Starter Kit by Abbey Elder, as the "textbook" for the class. This greatly reduced the amount of work that I had to do to prepare materials for the CoP.