Most people's first real session looks the same: register a repository, create a workspace, and have one real conversation in it. That loop alone is often enough to be useful — see Create your first workspace if you haven't done this yet.
Once that feels natural, the next thing worth trying is a Domain — write down the handful of things about your codebase you find yourself re-explaining, attach it to the workspace, and notice how much less context-setting the next conversation needs.
From there, Agents are the natural next step: assign one to a workspace and watch it pick up new messages on its own schedule, instead of you having to open the app and hit send every time. Strategies are the most advanced layer — once you've manually wired two agents together once, save the pattern so you never have to build it from scratch again.
None of this is required to get value out of DF Code on day one. It's meant to be grown into, not configured up front.