How do we organize an HLS stream using restream.io?

Question

Video broadcast

Hi friends.
We have a children's TV channel with our own content for difficult children.
The channel operates 24/7, is currently available outside the Russian Federation and only in private hospitals and clinics.
Broadcasting goes from OBS Studio via the restream.io service to private RTMP.
For our part, we only give the stream, and all other frauds take place on the side of the clients and the restream.io service itself. Now we have a client that requests an HLS stream from us for restreaming.
Because We don't know much about this so we don't know what to say.
Googling the HLS topic, we roughly understood what it is, but we still don’t understand how we organize the transfer of the stream.