A logical structure supports a clear and focused message, and it stops you from leaping from idea to idea, which can make it difficult for your audience to understand your talk.
Trent University. (n.d.). Preparing and delivering oral presentations. https://www.trentu.ca/academicskills/how-guides/how-write-university/how-approach-any-assignment/preparing-and-delivering-oral
University of Sussex. (n.d.). Preparing for a presentation. https://www.sussex.ac.uk/skillshub/?id=310&site=normal