Demonstrative Adjectives

These are used to indicate a specific noun or nouns. They go before the noun they modify.
este = this (for masculine nouns)
esta = this (for feminine nouns)
esto = this (when noun is not identified)

estos = these (for masculine nouns)
estas = these (for feminine nouns)

ese = that (for masculine nouns)
esa = that (for feminine nouns)
eso = that (when noun is not identified)
aquel = that (way over there) masculine
aquella = that (way over there) feminine
aquello = that (way over there) when noun is not identified

esos = those (for masculine nouns)
esas = those (for feminine nouns)
aquellos = those (way over there) masculine
aquellas = those (way over there) feminine

For a simple masculine noun like “libro” it would look like this:

This book = Este libro
These books = Estos libros
That book = Ese libro
That book way over there = Aquel libro
Those books = esos libros
Those books way over there = Aquellos libros

For a simple feminine noun like “casa” it would look like this:

This house = Esta casa
These houses = Estas casas
That house = Esa casa
That house way over there = Aquella casa
Those houses = Esas casas
Those houses way over there = Aquellas casas