The trick to building abs is to reduce body fat. It is necessary to establish a balance between the calories consumed and the calories expended. It is possible to reduce the fat rate when more calories are burned than the intake. In addition to weight training, cardio should be done, and permanent fat burning should be ensured with a patient, disciplined, non-boring, balanced, and sustainable high protein diet. Of course, I'm not an expert on this. But this is the information I got.