Learn Italian: Preparo la cena in cucina. - I prepare dinner in the kitchen.

In Italian, the ending of the verb usually tells you who is doing the action. The verb preparare (to prepare) changes to preparo for the "I" form. You can say io preparo, but Italians normally drop the io unless they really want to emphasize who is doing the action.

Why does the sentence say la cena ("the dinner") instead of just cena?

In English, we usually leave out the word "the" for meals and just say "I prepare dinner." In Italian, you generally need to use the definite article (il, la, etc.) before nouns, including meals. So, "dinner" becomes la cena.

Why is it in cucina and not nella cucina for "in the kitchen"?

When talking about being in or going to the rooms of a house (like the kitchen, bathroom, or living room), Italian uses the preposition in without an article. So, "in the kitchen" is simply in cucina. You would only add the article (making it nella cucina) if you were describing a specific kitchen, like "in Mario's kitchen" or "in the new kitchen".