How real world development works collaboratively.

I’m a student. I know Git and Github. I know how to use it. But I don’t know how multiple people work on a single project. Me and my friends tried it. Making a project collaboratively but we can do that in a better way I feel because the current method we’re using is just made different branch for each member and pushing code on that branch and when it’s time to merge the code we face a lot of problems. We understand the importance of meetings but we can do better. Just need a guide.