Zero copula in the present tense
In present-tense Russian, the verb 'to be' (быть) is invisible. 'I am a student' is just Я студент — three words become two.
What 'zero copula' means
Where English needs is/am/are, Russian uses nothing at all. You simply juxtapose the subject and the description. Я студент — I [am] a student. Он врач — He [is] a doctor. Это книга — This [is] a book.
The dash trick
When both sides are nouns, written Russian inserts a dash to mark the missing copula: Москва — столица. (Moscow [is] the capital.) Don't say it out loud — it's purely a punctuation mark.
Это — your new best friend
Это means 'this is / it is / these are / those are' — singular and plural, all genders. Это мама (This is mom). Это книга (This is a book). Это студенты (These are students). It never changes.
Asking 'what / who'
Что это? — What is this? Кто это? — Who is this? Use кто for people and animals, что for everything else.
