
The person who wishes to remove a mountain begins by carrying away small stones.

Nothing could be harder. The sitting is easy. But the "just," there's the rub! The habit of discursive-thinking, worrying, wondering, and drifting off is like an ocean current that pulls us away from this moment.
"Be here now." When? Now. Where? Here. What? Just be.
"It's too easy! Give me something to do, something to accomplish, something to cling to!" Okay. Do this. Become The Observer. Instead of doing, become a human being.
To be is to see. Watch. What's happening without your input? It's happening so often and without effort that it's easy to miss. What is it?

Keep watching. Relaxing and without effort or "thinking" (judging, evaluating, measuring, pondering, criticizing, questioning...), the breath may grow calm.
Keep watching. The real object of meditation is that subtle breath. It hardly moves. To notice it, attention has to grow stronger to keep up. The easiest thing -- and it may be needed -- is falling asleep because "nothing was happening." But something was.

Before levitating (the inspired lightness of just being), there is focusing, collecting the mind, concentrating it, gaining absorption (zen, jhana, dhyana), developing one-pointedness and equanimity, and samma-samadhi (right concentration). It all unfolds by itself.
Follow the breath and everything that's going on -- as a dispassionate observer. Be the watcher, the witness, the one who notices and keeps noticing/giving attention. It's the little things in life. To move a mountain, begin with the small stones. Just sit.