How do I install Merlin?

Could you please explain the process of installing Merlin in a step-by-step manner? I'm not very familiar with technical procedures and I'd like to ensure I follow all the necessary steps correctly. Additionally, is there a specific version of Merlin that is recommended for new users, or does it not matter which one I install? Also, is there a prerequisite software or hardware that I need to have before attempting the installation?