Learn Italian: La domenica andiamo a trovare i nonni. - On Sundays we go and visit our grandparents.

Using the definite article (la, il) before a day of the week means the action is a habit. So la domenica translates to "on Sundays" or "every Sunday". If you just said domenica andiamo, it would mean "this Sunday we are going".

Why do we use andare a trovare to say "visit" instead of just the verb visitare?

In Italian, visitare is used for places, like museums or cities, or for official appointments (like a doctor visiting a patient). When you visit people socially, like friends or family, you must use the phrase andare a trovare (literally "to go to find").

What is the function of the a in andiamo a trovare?

Verbs of movement, like andare (to go) and venire (to come), require the preposition a before another verb in the infinitive. While in English we say "go visit" or "go and visit", Italian connects the two verbs with a.

The English translation says "our grandparents", but there is no word for "our" in the Italian sentence. Why?

Italian often leaves out possessive adjectives (like i nostri) when the context makes it completely clear whose family members you are talking about. Since the verb is andiamo (we go), it is naturally assumed you are visiting your own grandparents. If you wanted to specify, you could say i nostri nonni.