We are migrating our modal based wizards to be "flat" and included in the main navigation system. They should be accessible via a navigation bar. How do we place the different buttons and explain the user that he is inside a wizard process? How do we prevent the user to exit the wizard before completing it? (or at least explain that he should complete)?
The reason why most of the wizards are contained in the modal (at least the ones that I see around) are for the exact reasons that you mentioned in the question.
- Ensure that the user knows that they are in a 'guided' process/flow
- Ensure that the user completes the flow before exiting
Technically you can still do this within the main navigation view, but the challenge will be to try and address the issues in a clear and innovative way.
For an overview of the Wizard design pattern you can look at UI Patterns and make sure that you are focused on solving the correct problem with the wizard design pattern (since you could probably find alternatives as well).
The NNgroup website also has a good list of recommendations for wizard design, and they show not only the modal wizards, but also provide examples of the full window wizards that you can reference.
I suspect that your current design makes it slightly difficult to connect the wizard to the rest of the navigation, which might mean some rethinking about the information architecture. But please go through the references and this should help you refine the question and allow a more specific answer to be provided.