Demonstrative pronouns (this, that, these, and those) are pronouns that point to a specific entity in order to distinguish it from others. These pronouns provide us with information about what/who is being referred to.
Demonstrative pronouns can be used for both singular and plural, for objects near us in time/space and those distant in time/space.
Pronouns this (for singular) and these (plural) are used with objects near us, as in this example: These are the people who helped build our nation.
Pronouns that and those are used for objects that are distant.