How to report people?

I was wanting to report someone. How do I do that?

Take printscreens of the event, you need solid proof what happends so the GM that sees it knows exactly what happened. Telling your own side if the story is not evidence, upload the images to example imgur, open an ingame ticket (talk to gm) link the images, explain what happened and submit.

where do we report ?

You need to open an in-game ticket as explained over here.