Knowledge is what you've gained from studying and from personal experience. Beware, though, since studying (especially history) is based on what those in power have written and it is not always 100% correct. Beliefs may be more theory--what you think may or might be true, but isn't proven. Belief systems are also more opinion than fact.
I'm not really sure what you mean by this vague question. Are you asking how knowledge differs from what one believes about things in general? Or how knowledge differs from understanding, or from wisdom? Or are you asking how knowledge differs from "beliefs" in a religious sense?
Let's take the first case, beliefs about specific things. For example, when an anthropologist talks about the beliefs or motivations or ideas of our prehistoric ancestors, he is basically guessing. We have no actual knowledge of these things, because they were before history. But we do have information of primitive cultures we have come into contact with in the last four or five centuries, and we can extrapolate from that. We have the tools and building sites of primitive mankind, and we can see how that knowledge fits with other things we know (or think we know), and attempt to arrive at logical conclusions. In other words, we use what we know to make logical estimates about what we don't know.
In terms of knowledge as distinct from understanding, we place a new thing we learn into a matrix of things we already know and draw the logical connections to build a "big picture" of the world around us. We start as infants and continue this process all our lives. One can know many things, but if one sees how these things fit together into patterns with meaning, we may be said to understand. If we develop this further until we can essentially pick the "right" thing to do in a completely new situation, we may be said to have developed wisdom.
As for my last example, I consider my "beliefs" in a spiritual sense to be a combination of knowledge, all the knowledge I have accumilated, all balanced against one another and sifted through for "true" facts and "false" or mistaken or misunderstood bits of information, combined with experience. Knowledge of bits and pieces is not enough, a wide-ranging knowledge combined with understanding and experience is necessary before one can know what is "true" about almost anything, "religious" or otherwise.
I have no idea from the phrasing of your question if this is what you're after, but there you go.
A very good question. Knowledge is what you know, and belief is what you believe. Unfortunately neither of the two need to be always true. Yes, knowledge need not always be the ultimate truth.
There was a time - I think about less than 100 years back - when top scientists of the world believed that the smallest divisible particles of matter are neutrons, protons, and neutrons, but now scientists believe that those three particles are composed of around twenty types of different particles. Now can we say that the belief of present day scientists is true knowledge and belief of the scientists a century ago were just their follies. Is this not confusing?
The reason for the confusion is that there is no absolute knowledge. Ultimately every knowledge rests on the foundation of acceptance of some belief that cannot be proves. Take the example of nature of simple thing like light. Scientists know that light is some kind of wave. But their problem is that any wave to exist thee mus be a medium in which wave occurs. They solved this problem by assuming that this world has to be pervaded by some medium. They have no way to know its nature or prove its existence, but they assumed it exists. Without foundation of this belief, they cannot explain a lot of things they know to be true.
Have I confused you more. Well there are a few things which are better acceptd on faith than known through logic.