Which terminal of Narita Airport are you expected to use?
(Currently in NRT Terminal 3, there is no railway station.)
By what time do you have to get to the boarding gate?
is it right that i dont have to board off the train, and just stay on the train until it reaches Narita airport Yes.
Please note that you cannot reserve a seat in that train.
There seats are secured on a first-come, first-served basis.
The 25th of July 2018 will be a weekday.
You may encounter a commuters' rush,
especially on the Toei Subway section (until Oshiage Station).
(For the Keisei section,
I suppose most passengers travel in the opposite direction.)
we can use IC card : pasmo/suica/icoca card for taking this sky access train right? Yes, though actually there are no "Sky Access" trains.
Two similar names are used confusingly.
http://www.keisei.co.jp/keisei/tetudou/railmap/railmap.pdf: Narita Sky Access (Line) is one of the two Keisei routes
connecting (Keisei) Takasago [KS10] and Narita Airport [KS42] Stations.
: Access Express [Access Tokkyu] trains
go not only on Narita Sky Access but also
either on the section (Keisei) Ueno [KS01] -- (Keisei) Takasago [KS10]
or on the section Oshiage [KS45] -- (Keisei) Takasago [KS10].
: The symbol color of Keisei Access Express on the route map is orange.
Toei Subway Kuramae Station (E-11, A-17)
is divided into two separate buildings, depending on the lines.
(Please pay attention also to the name of the line.)
The Oedo Line part and the Asakusa Line part
are a few hundred meters apart from each other.
https://www.kotsu.metro.tokyo.jp/subway/stations/kuramae/i/solid.pngDirect trains for Narita Airport depart at Track 2 on Asakusa Line.
Entrance A0 is close to the ticket gate.
(Entrance A3 is currently closed.)