What is MAPO sauce made of?

I'm curious to know, could you please elaborate on the ingredients that comprise the famous MAPO sauce? I've heard it's a staple in Sichuan cuisine and I'm eager to understand the flavors and textures that contribute to its distinct taste. Are there any specific spices or oils that are essential to its creation? Additionally, is there a traditional method of preparation that is widely followed? I'm eager to learn more about this intriguing condiment.