For the butt to appear, you need to create conditions under which your muscles will grow . And they grow when you do training with heavy weights : on them muscle fibers receive micro-breaks, they subsequently regenerate, and the muscle increases in volume.
Ideal for this is gym - there is a barbell, various simulators, dumbbells of different weights, with which you can create a load that suits you.
In any exercise you need to take such a weight that you have enough strength to do no less than 6 repetitions and no more than 12 repetitions - this promotes muscle growth.
Such exercises will work well : squats, lunges, gluteal bridge, leading the leg back in a crossover , dead and Romanian cravings, etc.
It is equally important to change your diet e. You should not starve, on the contrary, you need a calorie surplus - you need to consume more than you burn. Emphasis should be placed on complex carbohydrates (cereals, pasta from t / s wheat) - they give energy and strength, as well as on protein food (meat, eggs, cottage cheese, fish , soy products, seafood, legumes) - it promotes muscle growth.
Here it also depends on the figure, which is given by "nature" \ genetics. There are girls who look at their ass and "BAM", the trunk is gorgeous, and in some cases it seems like wide hips, but ... Ce la vie. And no matter how much they tried to pump up or reduce ... There were no special changes in either case.
Accept your body as it is. But this does not mean that it is unnecessary to play sports or eat right. I am leading to the fact that Kim Kardashian's ass cannot be pumped up, but you can have a fit and beautiful ass, Maxim wrote everything correctly, except for classes every day ... The body needs a day of recovery. 3-4 days a week for training is enough.
And more. Don't just focus on your butt. A pumped up ass and flabby arms or belly will not look good, is aesthetics important to you? Feel how the muscles work. If, during the exercise, you do not feel how the buttocks are straining, then it is better to work on another muscle group, since the priest no longer works, either the thighs or calves are working. Do the exercises correctly (that is, strain those muscles that you are working on). This is very important.
1) Good nutrition (More vegetables, less animal protein)
2) Eight an hour's sleep.
3) Regular training (you cannot skip the trainer / leave the regime) AND PATIENCE.
Three components that will give you not only a beautiful butt, but an overall beautiful body.
I will say it as a professional athlete. To pump things up, you need to adhere to strict rules.
Eat healthy food that you can make with your own hands. (Preferably: boiled, steamed, baked, not greasy or spicy)
regularly go in for sports, in this case squat with a barbell, run, do gymnastics (for more details on what exactly exercises need to be done besides squats and jogging, you can find in Google or Yandex)
You need to go in for sports not once 1-2 weeks, but every day.
Do not smoke, do not drink, try not to sit and lie a lot so that there is no cellulite.
In principle, I think these are the main things that need to be observed.
I advise you to consult a coach in the gym, because he works with this more often :)
Good luck you