Reading groups are a great way for people with different interests and levels of experience to share knowledge and percolate ideas in a collegial setting. We recommend finding at least 4 colleagues to participate so that the group doesn't fizzle if one person can't make it. While having colleagues in the same room is fantastic, there is no reason that a reading group can't be just as (or more!) successful over video chat (How to set up a group hangout on Google)
A common reading group format is to select one person every meeting to lead the discussion. Typically, the leader gets to choose the paper that everyone will read for that meeting. During the meeting, the leader will cover the paper section by section, offering questions and comments to the group to begin a conversation. Ideally, the paper is in an area that the leader is excited about and they can incorporate other work or interesting extensions into the discussion.
Of course, learning a difficult topic together is often a reward in itself. If no one in your group is familiar with a field try to start with an older paper that the paper you're interested in cites. With a group of curious compatriots and a bit of patience, even the most tricky syntax and concepts are within reach. Enjoy!