The Identity Ecosystem Steering Group is a multi-stakeholder organization (See this post about how join.) Technically You can participate on lists even if you are not members but it is better that you go through the process of joining to be “officially” part of the organization.
If you join the IDESG it is good to actively participate in at least one active committee because that is where organization work is done by committees – any person or organization from any stakeholder category can participate.
The committees have mailing lists – that you subscribe to (below click through where it says Join Mailing list and put in the e-mail address you want to use, share your name and also a password).
On the list the group chats together on the list and talk about the different work items they are focused on. They have conference calls as well to talk together (these range from once a week to once a month). You can also contact the chair of the committee and “officially” join but that is not required.
If you are reading this and getting involved for the first time – read through this list and pick one of the committees that sound interesting to you. They are friendly folks and should be able to help you get up to speed – ask questions and ask for help. This whole process is meant to be open and inclusive.