El FUTURO INMEDITO is like the English I am going to …, e.g. I am going to go, He is going to play, and is made up of the present tense of IR (to go) + a + the infinitive of the main verb:
Voy a salir (I am going to go out).
Vamos a comprar una casa (we are going to buy a house).
Va a llover (It is going to rain).
This is the most useful future tense to learn, as it is the one used most frequently in conversation when talking about the near future: esta noche (this evening), mañana (tomorrow), muy pronto (quite soon)… or when you would use “going to” in English.
But be careful not to mistake the near future with the present progressive:
Voy a comer una ensalada (I am going to eat a salad).
Estoy comiendo una ensalada (I am eating a salad).