set the scene idiom
描述实况;叙述背景
to describe a situation where something is about to happen
First, let's set the scene - it was a dark, wet night with a strong wind blowing. 首先，我们来描述一下故事发生的背景——那是一个漆黑的夜晚，下着雨，狂风呼啸。
（为…）做好准备（或铺垫）
to make something possible or likely to happen
His resignation set the scene for a company crisis. 他的辞职引发了一场公司危机。