LaserGRBL currently only supports importing GCode files, not DXF files. However, there are software programs available that can convert DXF files into GCode files, which can then be imported into LaserGRBL. One such program is called Inkscape, which is a free and open source vector graphics editor. You can import your DXF file into Inkscape, convert the file into a series of GCode commands, and then save the file as a GCode file. You can then import the GCode file into LaserGRBL and the laser should be able to execute the commands.