How can I legally use another creator’s work in creating my work? Don’t artists collaborate, sample, or riff on other artists all the time?

Any good collaboration begins with a conversation, and you can use another creator’s work so long as you have permission, such as a license, from the applicable original creators, or permission under the law (which can be difficult to determine). 

As a reminder, by agreeing to UnitedMasters’ Terms of Use, you agree that all content you distribute will not infringe upon the rights of any third parties.