Concrete is a material composed of 3 materials aggregates, water, and cement. When the water and the cement are mixed together with the aggregate, a hardening process starts which binds everything together so that it becomes a hard and solid mass.
The curing for concrete starts immediately when water and cement are mixed, for the best possible curing is about 20 celsius perfect then curing the concrete quickly and you can walk on it after only a few hours. when the temperature drops, it will harden more slowly. If the temperature goes below minus degrees, the water will freeze and the concrete will be completely destroyed and, in most cases, will never become strong concrete. If the temperature is much higher than 20 degrees, it will harden, but dry too fast and may soon crack in the surface. It is important for the concrete to retain the moisture to harden.
There are many ways to finish the concrete surface depending on how you want it to look. If you want to go over the surface you will have it smooth and smooth, it is a concrete floor out you want to have a brushed surface for better grip when it rains, or in winter when there is ice and snow. If the surface should be nice to look at, you want to polish the concrete, or maybe it is enough with a steel tray to smooth with.