Every new organization starts with sample content so you can try editing, tracing and reviewing without worrying about mistakes.
In the Items tree in the left sidebar you will find three top-level items:
Welcome to Trace.Space, a short introduction with a product demo and links.
Sample project, which contains Operating High Altitude, Long Endurance (HALE) Unmanned Aircraft Systems, a requirements document originally published by NASA, broken down into sections and requirements using a set of example item types and dropdowns.
Playground, an empty testing ground where you can create, import, edit and delete anything; delete it when you no longer need it.
Edit, trace, delete and restructure the sample content as much as you like. When you are ready to bring in your own data, delete the sample items or leave them in place; they do not affect anything else in the organization.