Etheric substance is life force. It is energy. It is as well sometimes called bioenergy.
What our eyes see is only the grosser or visible part of our life force. It is flesh or matter.
On the etheric level, you can perceive a different set of forces and energy.
At this stage, not much is known about the etheric body.
Most of the knowledge on this topic comes from the occult field.
The scientific field tends to deny its existence or at least its importance.
It acknowledges the existence of an electro magnetic field in and around the body but it’s implications and functioning are not yet deeply explored.