In Spanish, the future tense is formed by adding the following endings to the infinitive form of the verb:
-é
-ás
-á
-emos
-éis
-án
For "poner," the future tense would be:
yo pondré
tú pondrás
él/ella/usted pondrá
nosotros/nosotras pondremos
vosotros/vosotras pondréis
ellos/ellas/ustedes pondrán
For "salir," the future tense would be:
yo saldré
tú saldrás
él/ella/usted saldrá
nosotros/nosotras saldremos
vosotros/vosotras saldréis
ellos/ellas/ustedes saldrán
For "venir," the future tense would be:
yo vendré
tú vendrás
él/ella/usted vendrá
nosotros/nosotras vendremos
vosotros/vosotras vendréis
ellos/ellas/ustedes vendrán
Note that for all three verbs, the stem of the infinitive remains the same and the same endings are added to form the future tense. Also note that the verbs "poner" and "salir" are irregular in the future tense, meaning they don't follow the regular pattern of adding the same endings to the infinitive stem.