Learn Hardcore Spanish (Latin America): Corro con mi perro a la escuela.

We use a la escuela to emphasize direction or destination (running to the school). Para la escuela would suggest a different meaning, like running for the school’s benefit or with the school in mind, which isn’t implied in this sentence.

Why is it corro and not corre?

In Spanish, corro is the yo (I) form of the verb correr, which matches the subject I in English. Corre is the él/ella/usted (he/she/you-formal) form, so it would mean he/she/you run rather than I run.

Do we always need mi before perro?

If you want to express possession (it’s my dog), yes. Without mi, it would simply be el perro (the dog) or un perro (a dog), losing the idea that the dog belongs to you.

When do we usually use con?

Con generally means with and indicates accompaniment. Here, it shows that you are running together with your dog.