Your body
These four numbers are used to estimate what your body burns just keeping you alive: breathing, pumping blood, staying warm.
A normal day, not counting exercise
This is the question other calculators get wrong. Think about your job, your commute and your evenings. Ignore workouts completely. You'll add those next.
Deliberate exercise
Only sessions you'd actually call a workout. It gets spread evenly across the week, so a rest day and a gym day give the same daily figure.
What you want to happen
Eat your total and your weight holds steady. Eat under it and you lose; over it and you gain. Everything else is detail.