Note! Before proceeding, please make sure that you have a USB flash drive at least 8GB in size. All data will be destroyed on this drive, so please back up your files.
A few comments have mentioned easier ways to make a bootable MacOS USB drive:
this blog post uses UltraDMG and has worked for some (and is easier)
if using this archive.org page people have mentioned after Restore with Disk Image in Step 3, the USB is ready to boot and you can skip straight to Step 4.