Hold your position
保持姿势

Excuse me. Would you mind taking a picture for us?
打扰一下，你介意为我们拍张照吗？
Of course not. Just tell me how to operate it.
当然不介意了。告诉我怎么操作照相机就可以了。

It's simple. Just press the button, like this.
很简单，按这个按钮就可以了，像这样。
I know. Hold your position and say cheese.
知道了，保持姿势说：cheese。
Thank you.
谢谢。