Head to the clip or podcast episode that you would like to add chapter markers to.
Open the editor for that clip and click "Edit audio" in the top right.
Seek to player head to the point that you would like to add a chapter marker.
Click add chapter and give your chapter a name.
Repeat from step 3 until you've added all your chapter markers.
The Omny Studio embed player displays chapters and allows your listeners to easily navigate to different sections of your clip.
As do the Omny.fm web player.