The VSSIG is using a Slack Group: https://vocabulary-services.slack.com/ to continue the development of the workplan. To get an invitation to the channel, visit http://bit.ly/rda-vssig-slack-invite, or contact one of the group chairs.
The VSSIG has a number of task groups formed around particular topics. If you want to propose or sign up for the task groups, there is a groups sign-up page with instructions.