How are mantels attached to the wall?

Could you please explain to me how mantels are affixed to the wall? I'm quite curious about the installation process. Do they require special brackets or fasteners? Are there any specific steps that need to be followed to ensure they are securely mounted? I'd also like to know if there are any materials or tools that are typically used for this task. Additionally, are there any safety considerations that should be taken into account during the installation process? Thank you for your assistance in clarifying this matter.