This is the 107th most frequent Dutch word.
extra
The Dutch word "extra" means "additional" or "more than usual" in English.
In this sentence, 'extra' describes an additional required or requested aspect, making it an adjective for 'help'.
Hij vroeg om extra hulp bij zijn project.
He asked for extra help with his project.
In this context, 'extra' qualifies the noun 'chairs', indicating additional ones to serve a specific need.
We hebben wat extra stoelen gepakt voor de gasten.
We got some extra chairs for the guests.
Here 'extra' is used as an adjective to describe the additional needed element: 'time'.