If you have a pull-up bar, a resistance band for your level, an area to do push-ups, the only obstacle in front of you is how much you want it. you need to know the principles of muscle growth (progressive overload, mechanical tension, training to failure) and apply them to exercises that can be done with body weight. you need to work a muscle 2-3 times a week instead of 1 time and still pay attention to your nutrition. 3-4 workouts a week will be quite enough.
Those who say "no, you can't build muscle" mean if "you can't isolate very well", yes I agree, if you're working out at home you have to be a little creative. but if they mean that you can't grow muscle, turn around and don't even care.
