Behave oneself does mean to act properly, to not do anything that you should not be doing. Your sentence is not quite correct. "Behave oneself" doesn't apply well to a presentation, it is more for informal situations or for children. For example: If you are going to a party with people you work with, it is a good idea to behave yourself, and not drink too much or talk too loudly. Another example (to a child): "If you behave yourself while we are at the store, we can have ice cream when we get home." Hope that helps!