Am Maintain To Stay Fit Healt

I am having a little difficulty with understanding your question but I am interpreting it as
"I have been maintaining my weight but have just started exercising. What do I do with my calorie intake"

Assuming this is the question, please weigh yourself, enter your stats into MFP set to maintain weight. Log your food. Log your exercise (either using a linked fitness tracker OR machine data OR MFP estimates. Eat back a portion of your exercise calories (say 75%) then weigh yourself in four weeks time.
Multiply any difference in weight by 3,500 if you measure in lbs or 9,000 if you weigh in kg. if you lost weight, this was an unintended deficit. If you have gained weight, this was an unintended surplus. You can then adjust the percentage of exercise calories eaten. Repeat for another four weeks and so on until you maintain.