When to use a

I do not understand the rules for using the "a" In lesson 2>2 (Weekend plans) They use the following . Voy manana No voy en bus Then they use voy a nadir voy a la playa Why isn't the "a" used after the Ir verb in the frist first two sentences.

Voy manana says "I'm going tomorrow" If you add an "a" it would say "I'm going to tomorrow". No voy en bus "I'm going by bus. Again, it doesn't need the "a". Voy a nadair - I'm going "to" swim. Voy a la playa - I'm going to the beach. Note that in the first two sentences you are not "going to" somewhere, those two express when you are going, or how you are going. If, for example, you were going to the bus station instead of going by bus you would use the "a". From my understanding the "a" in these cases and many others is used like the English "to". It is used if you are "moving toward" something. Donde estamos? Where are we? A donde vamos? Where are we going? The "a" in Spanish is a complicated little word as you will learn, and can be translated many different ways depending upon it's use. This is a common use, but certainly not the only one that might confuse you in your studies (at least it has certainly confused me at times!)