Translation:If you were not to go to school, you would not know how to read
The sentence is OK in English but it doesn't mean someone knows how to do something, but rather more that they should do it. When he cuts oranges, he knows to use a knife instead of a spoon. When he's making a recipe, he knows to read the ingredients. When you get dropped in deep water you know to swim to shore. It's a bit strange, but I have heard it used in normal speech. However, in the context of going to school, I think it should be how to, since that's what they teach there.