To set up editors, you must configure the Wiki module Settings to allow Edit permission for Registered Users or whichever users you like to grant rights to write topics. Grant the same Edit permission for the Index module to allow whichever users to move topics.
Please note, granting edit permission here does not actually grant users the rights to create content yet. It merely sets them up as potential editors. You must explicitly grant topic editing permissions. Please see Manage permission for more information on granting topic permissions.
You can also decide which users are able to moderate comments and receive notifications for topic changes by granting them Moderate permission.