What's the difference between non-reserved and reserved seats? How about green cars, GranClass cars, and sleeper cars?

Non-reserved seat does not specify the train or seat number.
Reserved seat specifies the date of travel, train, and seat number.
Green cars are a rank above reserved seating in ordinary cars. GranClass cars are a step above green cars. Sleeper cars are cars that provide sleeping facilities.
Trains with seating above the rank of reserved seating in ordinary cars require a separate train fare ticket in addition to the Limited Express fare.