It's really easy. I'd be terrified if I had to make something on a grill. I'm sure I'd totally screw it up. And while I know how I like my steak--rare--I know others do not share my preference, and have no idea how to accommodate everyone.
It's all in the timing. Well done steaks go on the grill first, medium rare second and rare last. There is no need to flip a steak more than once and doneness you can test by poking them. The harder the steak the more it's cooked which I have mastered from years of grilling. Or you could use a meat thermometer but it's a sin to cut them or flip them more than once.
Last night I cooked 1 inch thick steaks 4 minutes on one side 3 on the other and they all came out rare. My aunt always like her steaks well done. I'd put them on 20 minutes before I'd cook the rare steaks.