Welcome to Week 4. Now, we're here in the course to learn what it is to go from idea to code, and that's important because A, you want to know that what you're investing in code-wise is going to be valuable to the user and the testability of that, how will you know if it's valuable or not, what is the testability of what you're building? Number 2, you will get lost in all the hooks and dials and complexity of the code, especially as you get zoned in and really dive into it, if you don't have some nice clear focal points in your design that you're able to work from. Now, that does not mean you should write a big long specification but I'm going to show you some design artifacts you've already been familiar with, user stories prototypes, that I think strike a good balance between creating focus and not over-prescribing the implementation before we go in and we transition to working software which is where we have to go ultimately to get something magical to happen. So there's a brief from HVAC, in a hurry, that talks about how they arrived at the decision to do what they're going to do, which I would have a look at, and then we're going to zero in on the user stories, the storyboards, and the prototypes that pertain to extending the design as you've seen it and how they're going to take the next step, for instance what happens when a HVAC technician clicks on one of these parts and sees the detail and wants to order it or wants to refine their search. So those are all options for you for your coding project for next week, ways to extend the design. My advice as you go through the brief is to pick something relatively specific like an individual user story or even an individual wireframe, party wireframe, tying those two things together. Don't try to do too much. If there's two things that interest you, pick one and put that as your top priority. If you have enough time and energy next week, you can go to the second one. But I would really focus on doing one thing well to your satisfaction so you don't run out of time and energy and overwhelm yourself because that is not the result I want for you. The other thing I would say is if you feel like you want to dive in and code and you're ready, it's up to you whether you want to modify some of these user stories and prototypes or not. I'll show you how to do it but it's totally optional, you can grab them and go. If you want to grab them and go and you want to start coding, that's absolutely fine. Get ahead on your work for next week, this week, that's absolutely fine if you want to do that. But I'm going to go through and I'm going to talk a little bit about some of the things that you're going to see in the design brief and why those are important and how they help you build better software, make a smoother transition from good idea to good code, and create a testable loop between those two things.