You cannot use anything you don't make yourself

Is the statement You cannot use anything you don't make yourself true in terms of  downloading things like music, video's and images from the internet?

This is not a true statement because with proper permission, you can use things that you have not made yourself. Some things are made accessible to the public and can be used for free even though you have not made those things yourself. So to say that you cannot use anything you have not made yourself is not true but instead it is better to say that, You cannot use anything you don't make yourself if you do not have permission.