Cannot install on a raspberry pi 3B (octopi)

[TomHVR]

Following this guide I get to the make step and it throws this error:

make ARCH=arm CROSS_COMPILE= -C /lib/modules/5.4.79-v7+/build M=/home/pi/rtl8812au modules
make[1]: Entering directory '/home/pi/linux-9797f1a4938c20139b00a25de93cc99efb5c291b'

ERROR: Kernel configuration is invalid.
include/generated/autoconf.h or include/config/auto.conf are missing.
Run 'make oldconfig && make prepare' on kernel src to fix it.

make[1]: *** [Makefile:704: include/config/auto.conf] Error 1
make[1]: Leaving directory '/home/pi/linux-9797f1a4938c20139b00a25de93cc99efb5c291b'