The answer to this question can be found in Chapter II of Mill’s work. There, he is laying out the basic ideas of his philosophy of utilitarianism. Let us look at his own words to see what things are actually desirable as ends. Mill says that
…pleasure, and freedom from pain, are the only things desirable as ends; and that all desirable things (which are as numerous in the utilitarian as in any other scheme) are desirable either for the pleasure inherent in themselves, or as means to the promotion of pleasure and the prevention of pain.
So, the answer to this part of your question is that the only things desirable as ends are pleasure and the freedom from pain.
But what does it mean for something to be desirable as an end? If a thing is desirable as an end, we want it for itself and not because we can use it to get something else. So, for example, money cannot possibly be desirable as an end. We only value money because we can use it to get things. If we could not use our money to buy anything, we would not really desire it. Mill says that pleasure and the absence of pain are the only things that we want for themselves, not as a way to get something else.