What do I need to remove to replace my starter?

Please excuse if I don't use the correct terms I'm definitely not a mechanic I just have fixed my cars as they break, but here it goes. I need to replace the starter in my car and the videos I'm watching on YouTube go from an untouched engine to everything already taken apart and then removing the starter without fully explaining what all I need to disconnect. I'm also curious if I disconnect the radiator hoses do I need to drain my radiator first? If so does that mean that I will need to bleed the air out of the radiator after I refill it? Also is it easier to handle this job underneath my car or above the engine? Because of course it's raining for the first time in a year in California so I'm not too excited about crawling underneath a wet car but if that's going to be the easiest way I don't mind