如果钥匙还在遥控器里，那么先把它拆下来。 拧下遥控器背面的螺丝。 如果遥控器边上有像卡槽一样的缝，可以拿一枚硬币插进去，然后把遥控器外壳撬开。 如果遥控器侧边没有宽缝，那么就只能撬开了。

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?
This depends on what kind of fob you have. Car key fobs for example typically hold the key when it is not in use. You have to open the key, although in some fobs the key is removable. Either slide the key out or spring it away from the fob.  A fob with a sliding key has a small button on the top. Hold the button down while pulling on the key to remove it. For a fob with a springing key, press the spring button on the fob or pull the key forward to get it out of the way. Flip the key fob over and