What puillin wrote is very good. If you drive, know that parking within is really difficult. However you get to the main part (where Bright Angel Lodge & other accommodations are), there is a great overlook. The scale is so huge it is hard to believe that the north rim is about 12 miles distant at that point.
At that area, you can get a free bus ride westward along the south rim, with many stops along the way. You can get off, explore, then catch the next bus that comes along.Or, you can hike to the next bus stop from any one.
Eastward from the main part can be driven, and there are many overlooks along the way that are spectacular. It is a long way to the main road back to Flagstaff, and besides the canyon, the other scenery is interesting. The painted desert is straight ahead. That road, 89A as I recall, is good. If you hit that, you can go northa little way and get to a really intersting Indian Trading Post.
Actually, getting in by car is far easier from that east entrance. The south (main entraince) often has horrendously long waits to get in. Traffic an be backed up for miles.
Other alternatives are a bus tour from Las Vegas or Phoenix, which may be the easiest way.
More cautions about the trails. In summer, it is very much hotter at the canyon bottom than at the rim. BTW, it is a mile straight down, and the trails are long and not easy. No matter what time of year, if you plan to hike down, take huge amounts of water. Not only is it hot, but very very arrid. There are no water supplies along the trails!
IIRC, reservations at Phantom Ranch on the bottom are full up for several years in advance. There are quite a few hotels and lodges inside the Park within walking distance of the rim, plus there are free shuttle buses that go around all the time.
Be sure and step outside at night and see what the stars look like from really dark skies!
There is an airport nearby from which you can get plane or helicopter rides, but I’m against that due to the noise they make and the disruption of the peace. Plus, every now and then one of them goes down with few if any survivors.