There is / there are – there is a printer on my desk

We use there is/are to talk about things in a particular location. There is for singular and there are for plural.
There is/are werden verwendet um über Dinge an einem bestimmten Ort zu sprechen. There is (“es gibt/da ist”) ist Singular und there are (“es gibt / da sind”) Plural.

There is a photocopier in her office.
There are a lot of people in the conference room.
There is a photocopier in her office. (“Es gibt einen Fotokopierer in ihrem Büro.”)
There are a lot of people in the conference room. (“Da sind viele Leute im Konferenzzimmer”).

To make a question just invert there and is/are:
Is there a photocopier in her office?
Are there a lot of people in the conference room?
Um Fragen zu bilden werden there und is/are einfach vertauscht:
Is there a photocopier in her office? (“Gibt es einen Fotokopierer in ihrem Büro?”)
Are there a lot of people in the conference room? (“Sind da viele Leute im Konferenzzimmer?”)

To make a negative use is not for singular and are not for plural
There is not (isn’t) a photocopier in her office.
There are not (aren’t) a lot of people in the conference room.
Um Fragen zu bilden wird is not für den Singular und are not für den Plural verwendet.
There is not (isn’t) a photocopier in her office.(“Es keinen Fotokopierer in ihrem Büro.”)
There are not (aren’t) a lot of people in the conference room. (“Da sind nicht viele Leute im Konferenzraum.”)

There is can be shortened to there’s in informal uses.
There is kann bei informellem Gebrauch zu there’s verkürzt werden.