祈使句表达操作步骤 — 英语阅读题

阅读短文，回答问题。 Making a paper fan is fun. First, take a square piece of paper. Then fold it up and down like an accordion（像折扇子一样一上一下地折）. Next, fold the whole paper in half. After that, glue the two open sides together. Finally, open the bottom（底部）and your paper fan is ready. Be careful with the glue and take your time! Question: What should you do FIRST to make a paper fan? Answer in one short sentence.