There are four very similar words that mean something kind of similar, this, that, these, and those, and all of these words indicate where something is located in relation to the speaker and whether it's singular or it's plural.
So I'm going to show you a little chart that I use to help differentiate between these four words. You can see two of the words are singular, this and that. They're used to refer to just one item. And you can see in this column these and those are plural. They're used to refer to more than one item.
If you look across, you can see that this and these are words that indicate something is near and that and those are words that indicate something is far. So to give you an example, I might say this pen is purple, those pencils are yellow. Or I might say these markers are colorful, those pencils are not very colorful.
Another example is that these books are heavy, but those pencils are not very heavy. So when you're using this, that, these, and those, just know that the word you choose is going to indicate how close something is to you and also how many of them there are.