when do you use "la" and "el" in a sentence?
using el and la
And there are double nouns which can be masculine or feminine depending on the region: la sartén / el sartén
And you use el on masculine nouns and la on feminine nouns, el dormitorio which means the bedroom and la puerta meaning the door and the plural of el is los so it is los dormitorios the bedrooms and las puertas the doors so as you see there are four different words that all mean "the" depending whether the noun that follows is masculine,femenine and singular or plural.
It depends if the sustanctive is masculine or femenine. You have to remember them all. But the most common rule is that the words finishing in "a" are femenine and in "o" is masculine.