First buy a ticket to Musashi-Sakai at JR Narita Airport Station together with a 
ticket for the Narita Express to Tokyo Station with seat reservation. 
(Fare:1890yen + N'EX 1660yen = 3550yen for one way.)
(You may be recommended to buy a ticket for Narita Express to 'Shinjuku', 
instead of 'Tokyo'. But buy a Narita Express Ticket to 'Tokyo'.)
N'EX Schedule :
7:43, 8:13, 8:43, 9:13, 9:43, 10:13, 11:13, 12:13, 13:13, 14:13, 14:43, 15:13, 15:43,16:13, 16:43, 17:13, 17:43, 18:13, 18:43, 19:13, 19:46, 20:43, 21:43.