what is the difference between "attend to school " and "attend to the school"?

Hola Sergio! Hay dos cuestiones:
1. Una es que "Attend" es distinto de "Attend to":
"Attend to school" significa prestar atencion en la escuela, mientras que "Attend school" Asistir a la escuela, "Attend a meeting" asistir a una reunion. "Attend+to" = prestar atencion y "attend" solo = asistir.
2. La otra es cuando agregar el "the" y cuando no:
"Go to School" sin el "the" es ir a la escuela a clase, a estudiar o a hacer algo que habitualmente se hace alli. Si decis "go to the school " implica que vas al edificio de la escuela a hacer otra cosa no relacionada con estudiar , por ejemplo: "the plumber went to the school to repair a pipe". Agregar el "the" es hacer referencia al lugar fisico, al edificio y por lo tanto necesitas aclarar para que vas al lugar.
De todas formas creo que en los casos particulares que mencionas yo las diria asi, aunque tampoco estoy muy segura:
I'm a student. I go to school.
I'm going to pick my kids up from school.
We had a parent's meeting at school yesterday.
I have to attend a parent meeting in the school's library at 7 tonight.
Espero no haberte confundido mas : ). Saludos Eugenia

Hi Sergio,
"attend to school" is like going to an unspecified school and "attend to the school" like going to a specified school or school as a specified institutuion. For example: My kids attend to school to learn something (any school), but I attend to the school to pick up my kids (which is a specific shool at a specific logation). Hope this helps. Saludos Era.

Hola Sergio, como te vas?

Honestly, I have never heard anyone say "attend to the school". You see, "attend" can mean "go", as in "I attend university", or "I attend those meetings". I means you go to that place, you are present. When you "attend + to" something, you are taking care of a task, giving attention to. For example, "the mother attended to her sick child". She helped, assisted, her sick child. "I have to attend to some business". I have to give attention to some business. So you could say, "After I attend the meeting, I must attend to some business". Or, "after I go to the meeting, I have to take care of some business". Esa te ayuda? Me entiendes?
Bueno... adios