• Use antes de + infinitive when the subject of both verbs is the same: Necesito leer… antes de almorzar.
• Use antes de que + subjunctive when the subjects differ: Necesito leer el documento antes de que empiece la reunión (“before the meeting starts”), because the meeting (it) is a different subject.
Both mean “I have to” or “I need to,” but there’s a subtle nuance:
• Tengo que often implies an external obligation (rules, boss, schedule).
• Necesito can feel more personal or internal (your own need).
In many contexts they’re interchangeable, though the shade of meaning may differ.
Add a demonstrative adjective or other qualifier before documento:
• este documento (“this document”)
• ese documento (“that document [near you]”)
• nuestro documento (“our document”)
For example: Necesito leer este documento antes de la reunión.
Yes. Depending on region and formality, you might hear:
• junta (especially in business contexts)
• sesión (formal session)
• encuentro (informal encounter/gathering)
• cita (appointment)
But reunión is the most general term for a meeting.