It depends on how big is the floor that will be coated. The first stage includes preparing the concrete floor like making some repairs, grinding, and cleaning it. This may take a few hours.
The second stage involves mixing the epoxy, resins, and hardener altogether, which may take a few minutes to incorporate all the ingredients.
After that, pouring the mixture onto the clean concrete layer and flattening it which may also take a few hours. On average, it takes 1-2 days to cure so people can walk on it. If vehicles move on the surface, you have to wait for 5 days for that to be allowed.