I am preparing a project for the school and I want to make a 2d game where to start

With the FAQ.

Subject: game design
I am preparing a project for the school and I want to make a 2d game where to start

Simla, you are not asking about game design. You are asking how to make a
game. Designing and making are not the same thing. As Lactose suggested, you should
start by reading the FAQs.