Final answer:
The correct forms of the verbs in the given sentences are 'vas', 'vamos', and 'van' respectively.
Step-by-step explanation:
1. El sábado, tú vas a la escuela.
2. Hoy, tú y yo vamos a la tienda de música.
3. Tus primos van a la zapatería.
Learn more about Using the correct forms of the verb 'ir' in Spanish sentences