Welcome to StackExchange! You are doing fine. However, just a tip. You may want to consider writing more details, try to be specific and show any research or resources. I'm fairly new myself and found out some people are pretty vicious on here.
a.) I am go to school for study English.
b.) I go school for study English.
I have bold typed your errors.
If you want to tell somone what you do now in general.
I go to school to study English.
If you are currently in process: You are moving your feet and walking right now you say:
I am going to school to study English.
This seems to be a common mistake you are making as well: for
In this sentence it is possible to say:
What do you go to school for?
I go to school for a class in English.