Perhaps you don't fully understand it, because it does make sense. Don't let Fil fool you into thinking it's absurd.
I am saying that reality, or existence, is in the mind. Many equate "physical" and "real", thinking that things that do not have physical presence in the world are somehow less real than things that do. That is ironic, because the impression that something is physical is an entirely conscious experience. You reach out and touch the wall. Real, solid. On a sub atomic scale it is not solid. It is just information, and that information is perceived by us, and it translates to hand meets wall.
There are no "things". There is just information. "Things" happen when relationships of information exchange are established, and some things become solid and physical, but only relative to other things. Were we humans to vanish, this human relationship with nature which we call reality, would be an irrelevant and incomprehensible "what if".