Hello, if you are 12 years old, you are still too young to do strength training, because your body still needs to grow and develop, so it is recommended to do more self-weight training, such as push-ups, sit-ups, flat support ..... all of which are good choices, but first you need to improve your basal metabolism (in short, the effect of losing weight will be better if this thing is higher), and the simplest way is running. You can't run blindly, and you can't stop running every time you feel tired to be lazy. Choose an amount you think you can stick to for the first time, and then add 100 m or 200 m at a time, so as to proceed step by step. The same is true for other trainings. Also, I suggest that children of this age should pay more attention to the training of body core. You can download an APP called Keep on your mobile phone, which contains many detailed action tutorials and a lot of fitness knowledge, which is of great help to you. Finally, remember a few points: 1, don't worry, don't blindly increase training, it will easily hurt yourself and affect your purpose. Remember to move forward step by step, this is the fastest and most stable way. 2. Don't be lazy. Since you have decided to change, don't give up easily. Losing weight is not a day or two. It takes a lot of time to work hard. Remember not to fish for three days and dry the net for two days! 3, don't do training for one part! Because losing weight is not just about losing a part of yourself because you are fat, which is unrealistic. Losing weight is comprehensive. Do more compound training and exercise all parts of the body. 4. Focus on core training! The core strength determines your explosive power and physical coordination ability, and also affects the shape of your abdominal muscles in the future. If you want to do strength training when you grow up, a stable core is very important to you!

All right, that's it. I am not a professional. I also learned it through my own exercise, my own exploration and my own reading materials. I hope it helps you! Lose weight and come on!