Bricks, Masonry, Asphalt and Concrete - Help with concrete!

I have never before worked with concrete so I apologize if I am asking silly questions. But I really need help. I poured today concrete to fill trenches I made in my basement concrete floor for under slab plumbing. I used QUICKRETE general mix that I bought in HomeDepot. I followed manufacture instructions and added 2/4 gal water to 80 lb concrete mix and thoroughly mixed them. Finally I got sandy paste that I poured into trenches (I backfilled trenches with gravel 4" below floor level so new concrete should be the same thickness of 4" as my existing concrete floor) and leveled concrete with existing floor level using steel trowel. Now what do I do next? Do I just let the concrete dry (for how long?) and that's it? And most important question: how do I make concrete mirror like smooth as my existing concrete floor? Since concrete mix with added water is actually like sandy paste I don't expect it to be smooth when it is completely dry?