Whether you have an existing package, are planning a re-write or creating a new package, design documents can help explain the problem you are trying to solve. In this talk, we will walk through AWSCore as a use-case, discuss what design documents are, their benefits, and showcase how they help users understand packages they haven't seen before. A design document is a written description of a software product, that a software designer writes to give a development team overall guidance to the architecture of the project. They include everything from the general architecture, internal/external dependencies, and in/out of scope tasks, among other things. When an individual or team starts contributing to a new package, it can be overwhelming at first. Finding out which components do what, how they interact with each other, and why certain design decisions were made. A design document can help clarify these general questions and get a new contributor started in understanding the package. Design documents are also helpful in producing an overview of the current architecture, showcasing alternative solutions, and explaining why certain design decisions were made. In this talk, we will discuss what a design document is, why you should consider creating one and what components go into it. By the end, you will know how to create a design document that will capture a snapshot of your package (or future package), outline guiding principles and summarize design decisions that will help lead to improvements in future revisions. Time Stamps: 00:00 Welcome! 00:10 Help us add time stamps or captions to this video! See the description for details. Want to help add timestamps to our YouTube videos to help with discoverability? Find out more here: https://github.com/JuliaCommunity/YouTubeVideoTimestamps Interested in improving the auto generated captions? Get involved here: https://github.com/JuliaCommunity/YouTubeVideoSubtitles