Confusing then and than is a mistake we frequently see online, even made by native speakers. Although their spelling and pronunciation may appear similar, they have very different meanings.
Than
Than can be either a conjunction or a preposition.
It can be used to join two parts of a comparison or used with 'more' or 'less' to compare numbers or amounts:
I am a lot older than my brother.
There are fewer people here than last year.
I would rather go to a restaurant than a bar.