: Place the microSD card provided with your printer into the machine's slot.
Since the file assumes a perfectly leveled bed at Z=0, you must adjust your Baby Z-Steps during the skirt/brim printing.
Learn how to troubleshoot common first-print failures on the Ender 3 Community Reddit
G1 X10.5 Y12.3 E0.0245 G1 Z0.3 F3000