I tried to make this step here. https://youtu.be/1rnA6wpF0o4?si=jXNYDYYGMOx8uZYH&t=1854
When I made make loader.o in Konsole, it displayed this error.

loader.s

makefile

kernel.cpp

linker.ld
N/A
What should I do here to proceed?
Thanks @AlgorithMan-de