Software development is an area where parallel development to its fullest form is very difficult to achieve, although you could get reasonably close with the right design. This is especially true for game development.

That being said, if you are designing a game from scratch from engine to front end, what steps should be taken in order? How would you efficiently manage your project and your team?

I'm asking because several people and I are interested in working on a relatively large project for learning purposes. Initially, we were going to use a proprietary engine like Unity, but since we wanted to learn how the engine works, we're going to start from bottom. I'd appreciate any suggestions that you guys can provide me.