Design-build is when you want to build something, like a house or a bridge, and instead of hiring one group of people to design the plan and another group of people to build it, you hire one group that can do both. Think of it like hiring a chef who can also grow the vegetables instead of hiring two different people for each job. By hiring one team to do both jobs, it can be faster and more efficient because they work together closely to make sure everything is done right. It's like a one-stop-shop for building things!