As Administrator, you can designate a member to be Challenge Sponsor for a specific community. A Challenge Sponsor can create and manage new challenges using an existing challenge template but does not have the full privileges and access rights of an Administrator. Challenge Sponsors only create challenges in communities where they have been give the Challenge Sponsor role and they can only edit challenges that they create.
Take a look at this short video to see how to select a sponsor for your challenge. Also see the Challenge Sponsor Checklist attached to this article.