Authoring file benefits from dedicated tooling. Main objective of such tooling is to support user with edition and validation. We all are used to leverage dedicated IDE when crafting software. Sadly, C4 DSL does not come with first class citizen tooling. To fill this gap and enforce consistency along the whole workflow, a dedicated Visual Studio Code extension has been shaped, aka Cornifer. While you could certainly achieve great results by other means, VS Code + Cornifer is the recommended stack to draw on.
Whether you are a seasoned C4 DSL author or plan to start your architecture as code journey, Cornifer extension will support you along the way. Coupled with Structurizr engine, it provides a top-notch architecture stack. Give it a try and start contributing to the code-first architecture community.