The reason you can't understand is because you think it using yo

In other words, Ego (the small separate self) trys to understand self less is almost impossible.  You are right that you shouldn't answer the question "Is the world real or not?", rather than answering the question, you should go beyond it and ask "Who is asking the question?", "To whom does this thought come?", The answer is obvious: "Me".  Then you continue to ask: "Who is this me?", "Who Am I?"

See, you turn any question or thought into a inquiry into yourself == "Who Am I?".

You don't try to answer "Who Am I?", you let the question float, and you will feel a quietude caused by this question, then stay in the quietude.

As soon as any thoughts come up in your mind, ask them: "To whom do they come?", answer: "To me", then ask "Who Am I?", gradually the period of quietness will expand and you will start to feel an uncaused joy...

The point is, never answer the question "Who Am I?" but keep asking, keep asking till the end of time, then, miracle will happen on its own, but you shall not expect it either.   It's that simple!