I expect you are getting Out of Bounds error messages. Lightburn will try to burn whatever is selected. The Workarea defines the physical limits of your machine. You cannot cut past those limits, so the design to be burned must be inside those boundaries.
The selection in your image (the lighter blue area) should be okay as long as you are using Line mode. But the overall project is much too large for your laser. Yhis is where some are using the Print & Cut feature.