Hola Giovanni
At the moment we don't have any lesson about accents, I'm afraid.
When we conjugate a verb in the vosotros form in the present tense there is very often a written accent on the last syllable. It also happens in the future tense. This is because we always put the stress on the last syllable when conjugating the vosotros form in these tenses. The possible endings will be: -ais/ -eis/ -is. As the stress goes on that last syllable and it ends on an -s, the accentuation rules say that it needs a written accent. Some examples are:
In the present:
- Vosotros habl-áis
- Vosotros com-éis
- Vosotros viv-ís
In the future:
- Vosotros llamar-éis
- Vosotros beber-éis
- Vosotros har-éis
Hope this helps.
Un saludo
Inma