It helps if you have an existing list of contacts to launch a community.

This is how most communities founded by amateurs begin. The founder reaches out to people they've known for years. They know these people are interested in joining a community.

Some organisations confuse a list of contacts with their list of customers. They confuse the people who know the founder personally and have developed relationships with the founder with those who purchase their products.

The difference is big, the latter feels like another marketing-led approach to get people to do something that you want. It's selfish and usually fails.

The better approach isn't to pretend you have good relationships with prospective founding members, but to build good relationships with founding members.