I want to preface this all by saying this guide is intended for those
who think they might enjoy engineering or using the 3D printers,
regardless of grade level. You might not know that answer now,
but if you think you might, give it a shot.
The software I used and the only one I can recommend is Fusion
360, as it's free for students given a computer that can run it.
You can always use computers in the engineering room if you
don't have one yourself.