There is no fast brother in fitness. To achieve a strong body, it takes time to accumulate and perseverance. There are many ways to exercise your muscles, and you don't have to go to the gym. From my own experience, I recommend you to do some heavy compound movements, such as push-ups, parallel bars arm flexion and extension, pull-ups, which can be done in daily life, but you must persist, and you will see the effect and fall in love with fitness.

Let me recommend a plan for you.

Push-ups in 5 groups, 20 in each group, rest 1 min.

Parallel bars arm flexion and extension 10 group 10 group rest 1 min.

5 groups of pull-ups, each group 10, between groups 1 min.

As a fitness instructor, I can tell you responsibly that all kinds of sports in the gym are not as good as these ancient sports. As long as you persist, you will get something. Even if you can't do so many combinations so many times at first, you can increase or decrease according to your own situation. The most important thing is persistence. Wish you success!