In English, the future tense cannot be used with certain time clauses. In other words, there are “no future in time clauses.”
An example may help:
When the packages arrives, I will sign for it.
In English, when your clause begins with:
When
While
Before
After
By the time
As soon as
If
Unless
…the present tense always follows (as in our example above).
In Italian, we use the future tense in time clauses:
Quando arriverà il pacco, lo firmerò.
When the package arrives, I will sign for it.
This is an area where Italian and English grammar diverge, so it is important to use proper tenses as you speak and write!