Hello, I am Yoshi from NILS Japanese language school.
[N1 は N2(place) です] *N refers to a noun.
Using this sentence pattern, you can explain where a place, a thing or a person is.
(Example)
①お手洗い（おてあらい）は　あそこです。　　　The rest room is there.
②電話（でんわ）は　2階（かい）です。　　　The telephone is on the second floor.
③田中（たなか）さんは　事務所（じむしょ）です。　　　Mr. Tanaka is in the office.
*お手洗い（おてあらい）: a rest room
*電話（でんわ）: a telephone
*2階（2かい）: the second floor
*事務所（じむしょ）: an office

[どこ／どちら]
どこ means “where,” and どちら means “which direction.” どちら can also means “where,” in which case it’s politer than どこ.
(Example)
お手洗いは　どこですか。　—あそこです。
Where is the rest room? —It’s there.

どこ or どちら is also used to ask the name of a country, company, school or any place or organization a person belongs to. You cannot use なん(what). どちら is politer than どこ.
(Eample)
学校はどこですか。　　　What’s the name of your school?

June 12th News, from NILS Japanese language school.