Verb conjugation of "suponer" in Spanish

My brother moved there last year. He met a woman and went after her. After six years they have broken up, but he no longer wanted to return, because he has settled down in his new home. I am visiting him once a year.
My name is Wolfgang, and I am interested to build my Spanish vocabulary. Maybe we can practice together. How long have you learned Spanish? I have been learning for a few years with books.
Three years ago I was with my friends in South Korea whom I met in my English class in Washington. Then I was in America for another three years, one in Oklahoma and two in Alabama.