Learn Spanish (Latin America): Vamos al evento juntos. - We are going to the event together.

The verb vamos already means we go or we are going. In Spanish, you usually drop the subject pronoun (nosotros) because the verb itself makes it clear exactly who is doing the action.

Why does it say al evento instead of a el evento?

When the preposition a (meaning to) is immediately followed by the masculine word el (meaning the), they must merge to form the contraction al. It is mandatory in Spanish to combine them!

Since this lesson is about con (with), could I use it here to mean we are going with each other?

No, to say you are doing something together as a group, you just use the word juntos (together). You use con when you separate the people in the sentence, like saying voy al evento contigo (I am going to the event with you).

Does the word juntos ever change its ending?

Yes! Even though it means together, in Spanish juntos describes the people and must match their gender. If the group going to the event is only females, you would say juntas. Because it is juntos here, the group is either all male or a mix of men and women.