Building my first Crisis Simulation and seeking best practices

We would often recommend browsing existing scenarios, as they can provide some inspiration for your own scenario when you go to create that. However, it is also worth mentioning that you can select pre-existing templates to build from, and these are great as they copy an entire scenario and provide you with a proven format to work with, while also allowing you to make amendments so you can include your own events, injects, and media throughout the exercise. 

Otherwise, if you are confident with exercise design and have a specific scenario in mind, you can choose to start from scratch and build the full scenario from the ground up! Ultimately, it is up to you, but using existing content can definitely help out as you build your first scenario.