Replying to Question for park crew guys

what goes into designing a park, is it just put stuff in as you go along, or do yall sit down and come up with ideas and come up with a full design. or is it somewhat in the middle. idk Im just very curious to know how this whole process goes down. also whats the timeline of this whole thing looking like. and is there any math going into things like building the jumps/bigger features, or is its just if it looks right. fuck so many questions