We use this/that/these/those to explain what we are talking about. We sometimes use them with nouns and we sometimes use them on their own.
'This' is used for things that are near to or in front of the speaker.
'That' is used for things that are far away from the speaker.
We use 'this' and 'that' with singular and uncountable nouns.
'These' and 'those' are used for more than one things. 'These' and 'those' is used with plural nouns.
'These' is used for things that are near and 'Those' is used for things that are far away.