You don't have to go to the gym, fitness is free, and there are many unarmed exercises for reference. The advantage of the gym is that the equipment is reasonable, which can train your muscles reasonably. If it is unarmed exercise, without the help of equipment, how to arrange the movements depends entirely on yourself. The most important thing in fitness is yourself. Adhere to reasonable training methods and reasonable diet. No matter where you are, you can keep healthy. Enjoy it.