Bắt đầu với một mảnh giấy hình chữ nhật.

I'm interested in that, but I only have a few mins. Can you give me at most the first 500 characters of a detailed explanation in English about that?
Ordinary loose paper or construction paper will do. We will make a square piece of paper from this. If you're already starting with a square piece of origami paper, skip the next two steps.