First you need to understand that if you want to have an ideal figure, you will have to train not only the buttocks, but also all other muscle groups, for example, slightly increase the shoulders and expand the back so that the waist looks narrower. You also need to understand that your result is not a figure on the scales, but an increase in the circumferences of priority muscle groups. Well, then everything is simple, follow a diet, having previously understood the principles of building an athlete's diet. www.youtube.com is a good video on this topic, but it is better to find literature. To master the main principles of organizing the training process, to study the technique of performing exercises, otherwise you can earn injuries to the joints and not only. tvoytrener.com is an excellent exercise guide, but other content on this site is not always accurate. You also need to take care of the source of motivation for you, this is really very important. I want to warn you against a few very common mistakes girls make in the sports hall. Do not do exercises on the oblique abdominal muscles, this will not save you from fat on the sides of the waist, but only increase the obliques, which will only make the waist wider, which is not what you want. Do not overdo squats, do not do quadriceps exercises, you will end up with too thick hips, and this is not always beautiful, it is better to do more deadlifts, hyperextensions and bends with weights, a bridge with a barbell will work best, so you can work out your hamstrings and buttocks without the participation of the quadriceps. But for the beginning, you need to strengthen the muscles of the back, do only hyperextension first, then go to the bridge, and then to the dead or bend. And finally, a couple of tips. Always listen to your body, a long diet and heavy physical exertion exhaust the endocrine system, which is why the growth of results stops even with the ideal adherence to the diet and the correct organization of the training process. Therefore, if you find yourself showing symptoms of overtraining, or do not progress for a long time, provided that all the conditions necessary for progress are met, take a break for a couple of weeks or a month, and then you will notice how the results start to grow again when you resume training. Do not neglect sports supplements, but do not overdo it with them, do not expect a miracle from them. Use them wisely, before you start taking something, read how to do it correctly, read, see what trainers and physiologists say about these supplements, is it worth taking them at all in your case, are there any contraindications. And now the most important thing is to take your training and diet as seriously as possible, do not listen to those who say that all this is nonsense, it needs a serious, systematic and deliberate approach. Do not read sports publics on VKontakte, as there is usually a lot of contradictory or simply incorrect information. Find literature on the topic you are interested in and look for the answer to your question there, this approach will be the most correct. Good luck with your training!
A thin girl needs to first determine her hormonal status. And if the girl's testosterone level is low, then you need to attend to finding a doctor who will be able to develop a course for raising it. For without this useful hormone, you will pump your ass until you turn blue, but rather unsuccessfully.
I'll give my own example. Height 168, weight 48-49. There was a catastrophic lack of weight: sharp shoulders, thin arms, the absence of a heel as such. There were also terrible problems with weight gain. I ate anything, as a result - a maximum of plus a kilogram on the scales, which then disappeared into some unknown place.
1) Enrolled in the gym
2) I began to observe nutrition, proper nutrition for gaining weight : 3 main meals, 2 snacks.
3) Workouts as scheduled, regular + healthy sleep
Bottom line: on the scales at the end of the month +5 kilos, + centimeters of the buttocks, round and toned nut, and the like) so that's all solvable)