1: The self, if it exists, is a thing that receives and/or controls experience. Some aspects of experience it controls, other aspects it receives. But whether the experience is "controlled" or "received", the self as controller or receiver is external to the experience. It's simple...if X is controlling Y then X is not the same as Y. If X is receiving Y, then X is not the same as Y.
2: It follows from 1 that the self is not the same as any experience. In other words, the self cannot be experienced.
3: Something that is entirely outside of experience...well it basically does not exist. In other words, the self does not exist.