When you apply it to the area it shouldn’t be more than ⅜ of an inch thick. You can smooth it out or give it a bit of texture using a plasterer’s rake or broom. If you’re happy with it, you’re done. Or you can wait 24 hours and add another layer of parging. Spraying it with a bit of water over the next few days. That will help the new parging dry slower, which decreases the chances of it cracking or flaking.