Without them, you're on a road trip without a GPS, and you have no direction. You don't know what success means for your project.
What I tell people when they say, "oh, I don't know what to do next", "I don't know my next step", "I'm not sure what the next step in my process should be", I always say look at the objectives.
If your objectives are written correctly, they should tell you what to do. That should be your roadmap for the rest of the project.