Hey!
Usually it's an individual thing with maintenance. When you reach your goal and are firmly there, you begin by increasing your calories (assuming you count calories) by, say, 100 a day and see what happens for a week or two. Then increase by another increment. You may see your weight continue to drop at first, or not. At some point your weight will level out, and if it starts to rise (and I'm talking about weekly weigh-ins, not daily), you stay at that calorie level or drop back by 100.
As for exercise, do the exercise regimen you plan for maintenance. It will likely mean fewer days at the gym per week, or less intense workouts.
You adjust these components on your own to see what gives you a steady weight, with a range of fluctuation.
Jay