While the process of building muscle at a cellular level is complicated to say the least, at the practical level, it’s quite simple.
…Building muscle can be simplified into one simple concept: increase the weight, repetitions (also known as “reps”), or volume that you can do in a given exercise. This concept is known as ” progressive overload.” The result is an increase in muscle size—a process known as muscular hypertrophy.
…What about heavier folks who are worried that they can’t perform bodyweight exercises? That can be solved by finding versions of exercises that you can do, such as kneeling push-ups or wall push-ups instead of regular push-ups. Don’t beat yourself up if you use an easier version of an exercise. What truly matters is improvements week over week.
Source: Are Bodyweight Exercises Effective?
What the article doesn’t discuss is oversight – having an instructor of some fashion monitoring, giving you feedback, and correcting where necessary. This is why though you can practice yoga on your own, I don’t recommend it. I’ve seen too many cases of chest facing forwards, but the hips are at 45 degrees. Or in foot position in warrior postures… It also takes a lot of self discipline to practice on your own – making time and thinking up lesson plans.
There is no best program, diet, or exercise. When it comes to fitness and health, everything is contextual and depends on the individual. Done correctly, bodyweight training will build muscle, but definitely consider your time, budget, and goals when selecting the program that’s right for you.