Learn Spanish (Latin America): ¿Vas a la fiesta?

In Spanish, the verb ending usually tells you who is doing the action. Vas is the "you" (informal) form of the verb ir (to go). Because the verb already means "you go" or "you are going," you can leave out the word tú (you).

Why are there no words for "Are" or "do" in the Spanish question?

Spanish doesn't use helper verbs like "do" or "are" to ask questions. You simply take a regular statement like Vas a la fiesta (You are going to the party) and add question marks and a rising tone of voice to make it a question.

The current lesson is about words like dónde and adónde. How would I ask "Where are you going?" instead?

To ask "Where are you going?", you would use the question word adónde (to where). The question would simply be ¿Adónde vas?. Since this specific sentence is a yes/no question about a known destination (la fiesta), it doesn't need a question word.

Why do we need the word a here?

The word a translates to "to". Whenever you use a form of the verb ir (to go) followed by a destination, you must use a to connect them, just like we say "going to the party" in English.