Do you remember what demonstrative adjectives are? Think back to French 101 (or maybe even English 101). Demonstrative adjectives are adjectives used to modify a noun so that you know which specific person, place, or thing is being mentioned.
In other words, “this, that, these, and those.” We have four of these in English (as just demonstrated), and four in French as well, although they aren’t exactly the same. Don’t fret, they aren’t as hard to remember as you think. Ce for singular masculine nouns, cette for singular feminine nouns, and ces for all plural nouns. There is also a special extra one, cet, which is used for masculine nouns that begin with vowels or the letter “h,” and pronounced the same as cette.
The main thing you need to keep track of, as always, is the gender of the noun. While they might seem inconsequential to a native English speaker, the articles that preclude nouns are really part of the words as a whole, and will be interpreted as such. But that shouldn’t be a problem for you. You’ve studied all your noun genders, right?