Ok so basically words r either feminine or masculine. So if it has la, las, or una it’s feminine and if it has un, el, or los it’s masculine. La and el is used for definitive singular. Los and las is used for definite plural. Una and un is used for indefinite singular. Unas and unos is used for indefinite plural. If ur making a word plural u add s if it ends with a vowel and es if it ends with a consonant. For example las mesas it’s la Mesa (definite singular) una Mesa (indefinite singular) unas mesas (indefinite plural). For el profesor (going across) it’s los profesores, un profesor, unos profesores. I hope this helped.
