Do you want to add before the instrument?

You don't have to put it in front of the instrument. Before Chinese traditional musical instruments, the definite article "the" is not needed before the noun of Chinese phonetic musical instruments. If you indicate a specific number, such as an erhu, use an indefinite article in front of it, which means that when playing an instrument, the instrument should be added in front.

The is a definite article, indicating a specific person or thing. It is used with singular nouns, adjectives or participles. Used in front of nouns indicating direction, before the names of rivers, oceans, lakes, islands and mountains, it can also refer to unique things in the world.