Learn Italian: Vanno alle riunioni presto. - They go to the meetings early.

alle is a combination of the preposition a (to) and the definite article le (the). Because riunioni (meetings) is a feminine plural noun, it takes the feminine plural article le. When you combine a and le, you get alle (to the).

Since riunioni ends in -i, shouldn't it be masculine? Why does it use the feminine alle?

Not all words ending in -i are masculine! The singular form of this word is riunione (meeting), which is a feminine word. Nouns that end in -e in the singular change to -i in the plural, regardless of whether they are masculine or feminine. Because the word is inherently feminine, its plural form remains feminine, which is why we must use the feminine alle.

Where is the word for "they" in this sentence?

In Italian, the subject pronoun is usually left out because the verb itself tells you who is doing the action. Vanno is specifically the "they" form of the irregular verb andare (to go). If you really wanted to emphasize who was going, you could say Loro vanno, but just starting with Vanno is perfectly natural and much more common.

I thought presto meant "soon". Can it also mean "early"?