sit down
The German phrase 'sich hinsetzen' is the equivalent of the English 'sit down'. It is a separable verb, where 'sich' is a reflexive pronoun and 'hinsetzen' is the verb. The phrase is used when someone takes a seat, often in response to an invitation or instruction.
Anita could sit down to read a book.
In this example, 'sich hinsetzen' is used to express the action of sitting down. It pertains to Anita deciding to sit down in order to read a book.
You must sit down when you eat your food.
In this usage, 'sich hinsetzen' represents the requirement to sit while eating. It pertains to a general rule or suggestion that one engages in.
We will sit down and discuss the situation.
In this context, 'sich hinsetzen' is associated with settling down to deliberate on a particular situation. The implication here is that the discussion will be thorough and possibly lengthy.