Finding your seat at N'EX?

Hi,
so this might be a silly question. I'm going back to Tokyo in a week and planning to take the N'EX from Narita to Shinjuku. I've been reading about it, and I understand you need to reserve a seat before you get on. But, do you get a specific seat and if so how do you find it easily?
Or do you just get a ticket for ordinary car/green car and take the first free seat you can find?
Also, how do the luggage storage locks work?
Thank you in advance, I overthink a lot and like to be prepared after a whole day of travel.

Since the N'Ex splits into two trains at Tokyo Station, you must specify where you are going. The salesperson will assign you a seat on a car that is going to that station. Once you arrive at the platform at Narita, there are placards on the ground that tell you where the doors to each particular car will open. When you find your car number, just line up behind the placard and wait until your train arrives. Remember that the train has to get to Terminal 1 before it starts its run back to Tokyo, so if you are at Terminal 2 and you see a train, it may be the train from Tokyo and it needs to finish its run. I'm sure there will be people getting off the train and that will tell you it's not the time to get on the train yet. Once it comes back, then you can board. Then it's just a matter of finding the row and seat. Simple.

Oh, the storage lockers.... It's just a shelf where you put your suitcase. There is a cable that is attached to a combination lock (4 roller/numbers). You place the suitcase on the shelf or ground, then grab the coiled cable and wrap it around the handle and place the looped end into a peg next to the lock. You then close the lock, set the combo to what you want and there is a lever you set to "lock". Spin the numbers so it's hard to read the combo. When it's time to retrieve your bags, set the number and move the lever to "unlock" and unwrap the cable from your handle and that's it. Simple.

Also, how do the luggage storage locks work?

If your luggage is not that heavy, you may just put it on the overhead rack above your seat, or next to you as many tourists do.

http://www.jreast.co.jp/e/nex/facilities.html

1)
http://www.jreast.co.jp/e/nex/index.html
https://en.wikipedia.org/wiki/Narita_Express
Btw NRT and Tokyo using 12 cars total as one train mostly.(not all)
For Shinjuku : car no.7 to 12 /6 rear cars until Tokyo
For Yokohama : car no.1 to 6 /6 front cars until Tokyo
https://www.eki-net.com/pc/jreast-shinkansen-reservation/English/wb/co...
https://youtu.be/iLuHADed1P4

Ticket :
http://www.railtourguide.com/wp-content/uploads/2014/10/narita-express...

Find Car number :
Door side display "blue" number is so.
https://youtu.be/-F7QdUbtOKI

Find Seat number :
http://userdisk.webry.biglobe.ne.jp/015/564/98/N000/000/002/1264426901...

2)
http://www.jreast.co.jp/e/nex/facilities.html
https://youtu.be/P9v9LZnOUGM (not NRT stn)
http://photozou.jp/photo/show/347454/67495942
How to use key lock by four numbers :
http://userdisk.webry.biglobe.ne.jp/030/787/66/N000/000/001/1446900230...
http://www42.tok2.com/home/dexef/contents/train_guide/jreast/e259/259-...
(Don't forget your key number.)

I believe all seats on N'EX is reserved. You will be assigned a seat upon purchasing the ticket. I put the luggage in front of my seat.

However, if you buy a return ticket, remember to reserve the seat for the returning trip, as the ticket will be open. Especially for the Tokyo-Narita trip as it could be full.

I believe all seats on N'EX is reserved.

I used to think that was the case, until my last trip a conductor in the NEX train told me that with JR pass you could still ride the train, but standing only. However, with plenty of empty seats , I doubt even the conductor would ask you to leave the seat.

That still makes all the seats reserved. Standing is not a seat.

That still makes all the seats reserved. Standing is not a seat.

My initial understanding of the rule was only reserved tickets holders allowed in this train.
I was only trying to share my experience that, in case of emergency, one could ride NEX without a reserved seat ticket.

Thank you all so much! I feel a little less anxious now. Now I'm just hoping that the two strikes they're talking about here at home (at the airport I'm leaving from and my airline) won't happen so I can actually get to Japan.

I used to think that was the case, until my last trip a conductor in the NEX train told me that with JR pass you could still ride the train, but standing only.

Hmm.. could that be a misunderstanding? I think JR Pass user can ride the train (for free) but seat reservation is still required. If no seat reservation, the passenger can still ride the train but standing (or sit by luck and move if the seat is taken).

During the Ikebukuro-Narita route, there's a group of teenagers, it seems it was their first time in Japan. At every stop, someone boarded the train and claimed their seat. Turned out they had a round-trip NEX ticket but did not reserve the trip back, thus they didn't get any seat and need to shuffle around. It not a peak season yet, but the train was almost full.

It is in fact true that you can board the N'EX without a reserved seat ticket. Namely, you can use what JR East calls an unassigned seat ticket in English (座席未指定券 in Japanese). https://www.jreast.co.jp/nex/charge.html

Unlike unreserved seat tickets (and standing tickets on trains where they are sold), an unassigned seat ticket costs the same as a reserved seat ticket. As its name implies, it does not assign you a seat; instead you can sit on any seat you want. (However, if a person with a reserved seat ticket for that seat comes up, they may of course ask you to leave the seat.) You may also convert it to a reserved seat ticket at no extra cost.

It is possible that riding the N'EX with only a JR Pass is equivalent to riding it with an unassigned seat ticket. However, this is impossible to confirm, as the complete rules for the JR Pass are not publicly available (as far as I know).

I rode NEX from Narita with JR pass last November and they assigned a seat for me.

I said "with ONLY a JR Pass", as opposed to "with a JR Pass and a reserved seat ticket". In that case you definitely do not get an assigned seat.

That still makes all the seats reserved.

That is not correct, please check:
http://www.jreast.co.jp/nex/charge.html#unspecified

It is absolutely correct that all the seats are reserved.

成田エクスプレスは全車指定席です。

Could anyone please kindly translate the following:

【座席未指定券】
●通常の指定席特急券のほか、乗車日・乗車区間のみを指定し、列車・座席を指定しない特急券「座席未指定券」を発売します。
●「座席未指定券」をご利用の場合、車内の空席をご利用ください。なお、乗車される列車が決まり次第、追加料金なしで列車・座席の指定を受けることも可能です。
●「座席未指定券」は、列車・座席を指定した現在の指定席特急料金と同一料金です。
●「座席未指定券」は、満席の場合でもご購入いただけます。その場合、デッキ等をご利用ください。車内に空席があればお座りいただけます。満席を理由とした払いもどしは出来ません。
※指定席特急券をお持ちでも、その座席を他のお客さまが空席として利用している場合があります。
※空席をご利用の場合、その座席の指定席特急券をお持ちのお客さまがいらっしゃいましたら、席をお譲りください。

http://www.jreast.co.jp/nex/charge.html#unspecified

See my message above.

One thing I did not mention in my message above is that unassigned seat tickets, like unreserved seat sickets, are valid for one day and can be used on any train on that day, even if the train is fully booked. (Of course in that latter case one has to stand for at least part of the way.)