How to make someone moderator for my yahoo group?

Here’s how to promote one of your members to moderator status: From the list on the left, click Members and locate the member on the Members page. Click Edit Membership. A little way down, click Change to Moderator. Click on the Make Moderator button to confirm. The moderator you appoint will have basic privileges in the group features you've made available, including Files, Calendar, Polls, Database, and Links. In these areas, the new moderator will be able to add, edit, and delete items, including items submitted by other members. You also have the option of assigning them advanced moderator privileges for the Messages, Members, and Settings areas.

You find them in your membership list. Click edit membership under their name or i.d. then you scroll down and click change to moderator and follow the prompts.