I will think, he will shout, you will die, ...
Pensaré, gritará, morirás, ...
— or —
Voy a pensar, va a gritar, vas a morir, ...
There are two ways to communicate future events in Spanish. In the first one, add an ending to the unchanged infinitive form of the verb. These same endings are used for all three types of verbs (-AR, -ER and -IR), which makes learning them easier:
Pensaré: I will think
Pensarás: you will think
Pensará: it will think
Pensaremos: we will think
Pensarán: they will think
Iré: I will go
Irás: you will go
Irá: she will go
Iremos: we will go
Irán: y'all will go
There are 12 verbs which change their infinitives before adding the ending, and they can be classified into 3 catigories: First, the "drop 'e's" are "querer," "poder," "caber," "haber," and "saber." Each of these loses the 'e' before the final 'r' when forming the future tense. These can be remembered by the mnemonic "Quick People Can't Have Sushi." Next, the "add 'd's" are "venir," "valer," "salir," "tener," and "poner." For these, the 2nd to last letter of the infinitive is replaced with a 'd'. These can be remembered by the mnemonic "Vroom Vroom, Said The Porsche." Finally, the verbs "decir" and "hacer" change their infinitives to "dir" and "har" respectively before adding the ending. These must simply be memorised.
Voy a saber: I am going to know
Vas a mentir: You are going to lie
Va a cazar: He/she is going to hunt
Vamos a contar: We are going to count
Van a poner: They are going to put