Introducing new members to the broader community is as important as hosting a kickoff event for new members to get to know each other. The larger the community the more alien things are for the new members at the start. That's true with any group set-up. The first time you entered a school you just joined, your first day at a new job - butterflies were always there in your stomach. Do everything you can to make the new members of your community to feel at home.
Here are a couple of tips to help them get comfortable from Day-0 and also for the community to get to know new members:
1) For smaller communities, this could be a post on the general Slack or Discord or Circle channel tagging the members
2)For larger communities, this could be a member directory that has a 'New to community' filter
3)Remind members of the community to welcome new members in the introduction channel
Dish - helps you create a member directory within your community