The existential there construction (There is/are + NP) introduces new entities into discourse. It is an information-structure device, not a locative; the there is a dummy (expletive) subject with no referential meaning.
There + be + notional subject (+ locative/temporal adjunct)
The notional (real) subject is the noun phrase that follows the verb. The grammatical subject position is filled by semantically empty there.
Existential there serves a discourse purpose: it presents new information in end position, where it carries greater informational weight. Compare:
This connects to the Given and New Information principle and Thematic Structure: English prefers given information before new. Existential there allows the speaker to delay the new referent to a position of focus.
The verb should agree with the notional subject:
In informal spoken English, there's commonly precedes plural nouns (There's lots of people here). This is standard in speech but considered non-standard in formal writing. See Subject-Verb Agreement.
Beyond be, existential there occurs with other verbs in formal or literary registers:
These are restricted to academic and literary prose.