To know of something but not know if it is true would be to believe. And in my opinion, a miss use of the word "know". There is nothing wrong with belief but, it is faith based and should be treated as such. One can Believe that they know something but be wrong.
Most people have accepted being taught something to be the same as knowing something and will defend what they have been taught as there own knowledge. Especially if it comes from a screen. It seems that more recently Wikipedia has become a "minister of knowledge."
Many of those who are pronounced to be the most knowledgeable of us actually know very little. To receive these accolades of so called knowledge, one must read, believe, remember and repeat what others have already clamed to know or, fail the numerous tests that one is required to pass before getting recognition as knowledgeable.
This process we call education strives to divide knowledge and true when in reality they intrinsic. To know something it must be true.
To Know how to do something is knowledge. To be able to do that thing is to combine your knowledge with your ability. One can know how to do something but not be able to do it. They could also Know that they Know how to do it, but still not be able to do it. For example someone who has done something in the past but is now disabled or no longer has the recourses.
Finally I would like to add another aspect of knowledge very seldom considered. The fact that knowledge can be a mater of opinion and still hold true. For example, you may know something is good because it truly is good for you. At the same time I may know that the same thing is bad, as it truly is bad for me.