As you said, losing fat and gaining muscle are two conflicting exercise methods. In view of your situation, I suggest two steps:
1, reduce fat
First of all, we should understand that fat can't be converted into muscle. Fat is evenly distributed, and it can't be just between the stomach and the ass. There is no way to reduce fat locally. So the first step must be to reduce fat. The most effective way is to do aerobic exercise persistently, such as jogging and swimming for more than 30 minutes every day. Eating at the same time, in short, avoid: soup, sugar, lying down, hot! The ratio of three meals a day is 4: 4: 2, and eat less at night.
2. Increase muscles
When your fat layer is reduced, congratulations, your muscles have improved a lot because of early exercise. At this time, if you exercise your muscles again, you will not be covered by a thick fat layer, and the effect will be obvious. During this period, pay attention to the nutrition of three meals, strengthen anaerobic exercise, and moderate aerobic exercise can clear the muscle contour. However, aerobic exercise should not be excessive, and excessive exercise will consume both muscle and fat!
According to your situation, as a physical education teacher, I estimate that the first step will take you about 2 months, and the second step will only take 3 months to get good results, depending on whether the landlord can persist!
By the way, to be more accurate, what you need to gain muscle is high-protein food, which is a material for synthesizing muscle! Such as eggs, milk, fish and meat!