A good place to start is The Social Church: A Theology of Digital Communication by Justin Wise. Despite the name, it’s a very easy entry point for people to start thinking about how churches can reach people, particularly millennials. I’d nab a few paperback copies for the staff and other leadership. I’ll summarize his process to approaching it a bit (from what I recall and what I’ve found helpful):
1.) The church has to discern what unique part of God’s mission they are called to fulfill: are they a church full of people who hit the beach and surf a lot? Maybe they are called to help the church in the broader sense by being the church in the smaller local sense for that demographic of unsaved persons. Look around and see where God has already positioned the church demographically/sociologically as part of discerning this aspect. You might find something odd like half the families have adopted children and discern that God has already uniquely positioned the church to reach families with adopted children; conversely, maybe you find out that a disproportionate number of your congregation were all-state wrestling champions and are uniquely positioned to reach out to families that have kids doing wrestling.
2.) Determine which one or two social media platforms to focus on based on that demographic your church has been uniquely positioned to reach: older demographics are usually facebook while younger ones are twitter, instagram, snapchat, youtube, etc. You need to assign one staff to each social media platform your church will use and they have to be able to be responsive to inquiries in a reasonable time frame (so it’s probably going to be a few hours a week kind of thing for them). Best to just start with the one where the most people from your demographic hang out.
3.) Develop a communication strategy wherein you determine who is going to the website and why, and how you are going to handle mass communications like email (what will be sent out, why, etc.). Assign one of the staff to it for a couple hours a week.
As for the email and ChMS, you may want to reevaluate solutions, having to manually dump emails to a list isn’t a good way to handle it, especially for non-technical people. Emails should be shot out through Mailchimp or Mailgun or something of that nature so either the ChMS is synced to an email list SaaS product or the ChMS is firing off through some email service like Mailgun. Of course, there are also fully SaaS solutions that would handle it end to end as well.