Cavalier King Charles Spaniels are not only lovely looking dogs they are also very eager to please this often makes them easy to train. If you have had a dog before then you will know that puppies need to be housebroken and taught acceptable behavior and this is also true of the Cavalier.
If you have only just acquired your Cavalier King Charles Spaniel puppy then with regard to training you should start as you mean to go on - and that means as soon as you get your puppy home. However small your puppy is he still has ways of letting you know what his needs are - it is up to you to keep an eye on him and learn his signals. This is especially relevant to toilet training, all dogs have a way of letting you know that they need to urinate or empty their bowels - this may be through chasing their tail, whimpering or going into another room. If you take the time to observe him going to the toilet and try to remember what he did first you will soon pick up on his signals. This is good for both your Cavalier King Charles Spaniel and yourself. Your puppy will be happy with the praise and petting that you give him and you will be happy with not having to clean up puddles in your kitchen or living room. In the beginning this will not always go according to plan but you will soon get used to each other's ways, you just need a little patience.
Once you have recognized your dog's particular signal then you should respond to his signal straight away - either by taking him outside into your garden or getting his lead and taking him out and staying with him until he has urinated or emptied his bowels. As time goes by he will recognize that you are responding to his signal and will soon let you know that he wants to go out. In order for this to happen you must be ready to respond to his signal straight away and then to praise him afterwards.
If your puppy is less than twelve weeks old then don't expect too much to start with - it is especially relevant at this point to keep your puppy to a limited area if you don't want 'accidents' all over the house and to keep a sheet of newspaper at one end of the space. Always clean up his messes straight away if he does have an accident and then he won't feel bad, don't scold at this stage. You will achieve more with your puppy if you just place him on the newspaper whenever he makes a mess and when it comes to the point where he goes there himself give him plenty of praise.
Between three and six months is when your puppy will develop some control over his waterworks and bowel and if you have been observing his signals now is the time to respond quickly to his needs. You'll soon realize when, besides last thing at night and first thing in the morning (when you should always simply take him out), he needs to relieve himself - usually a while after he has eaten, so keep a special eye on him at this time. Once he is about six months he will have a lot more control over himself and you should be able to take him out on a lead to visit other people.