To make your back bigger with calisthenics, focus on exercises that engage the entire back and use progressive overload. Progressive overload is when you gradually increase the amount of weight or resistance you are lifting over time.
For example, if you start by doing 10 reps of pull-ups, aim to do 12 reps the next time. This will challenge your muscles and help them grow. Additionally, you should focus on eating a balanced diet to ensure your body has the necessary energy and nutrition to build muscle.