I go to school / he goes (3 лицо, ед. число добавляем es) to school.
I went (2 форма глагола go) to school / he went to school
I will go to school / he will(вспомогательный гл. будущего времени.) go to school
I am going to school / he is going to school ( (am/is/are) +глагол+ing)
I have gone to school / he has gone to school ( have/has+глагол в 3 форме
go-went-gone)