Moderator role

  1. How to know which one is moderator, the first user who join the channel is moderator or their is nay other criteria for moderator role?

  2. How we can set specific participant to moderator using lib jisti low level api?

Thanks

You cannot, except when you are a moderator to grand moderator rights to another participant.
Moderator rights are handled serverside.

This is a server-side setting and depends on your deployment.