These words can go in front of any noun The articles you listed is the equivalent to the English word “the”. However, like in English you don’t need the word “the” in front of every noun you say.
Las and Los for when you are referring to an amount more than one of that subject.
La and El for when there is only one multiple of that subject.
Make sure you use masculine and feminine articles correctly. (La and las for feminine and el and los for masculine nouns)
The following are basic sentences with the articles used in a sentence:
The cake is delicious.
El pastel es delicioso.
The cakes are delicious
Los pasteles son deliciosos.
The plant is green.
La planta es verde.
The plants are green.
Las plantas son verdes.
