The usual way surrender happens is that you think: "I surrender." The usual way living in the present moment happens is that you think: "I choose to live in this moment and not to worry about the rest."
The true surrender, however, is not to be making a choice or doing the activity of surrender. Truly living in the present moment is not to think that you are choosing to live in it, but to know that you are the present moment, continuously and forever.
But you can't force yourself into those true positions. If you feel you are the doer, you must choose one of the first options, and hope you graduate into the second. If you do graduate, it won't be "you" who graduates; rather, the graduation will reveal that the you who thought you were surrendering or living in the moment was always a misconception, an incoherent thought. It wasn't necessary to choose surrender or live in the present moment; it wasn't even possible.