What relgion is the Holy Trinity Lutheran Church?

My great grandparents went to the Holy Trinity Lutheran Church my dad said it was a catholic church but wouldnt it be a lutheran church? what are the differences anyway. I went to sunday school as a child to a church that was down the street and that bible camp they had in summers to a chruch a few miles away, I stopped going because my parent were to lazy to drop me off and pick me up. I want to start going to a church again but I want to go a catholic one but I dont know what it will be like since I never been to one.