Can someone please explain the proof russels paradox? (sets - discrete maths) [on hold]

So I understand Russels paradox (barber) but I do not understand the proof, I've looked everywhere online and youtube videos but it doesn't seem to make sense.

Please note, I have compensated dyslexic so I find it hard to interpret and understand text. I think this is the reason why I am finding it difficult to understand the proof.

This is as much as I understand: P(x) <----> x is not a member of itself. What I don't understand is if it means the element x is not a member of itself? And if so, I do not understand how a element can be a member of itself.