just wget the file, edit those lines:
NETMAKER_BASE_DOMAIN=nm.$(curl -s ifconfig.me | tr . -).nip.io
COREDNS_IP=$(ip route get 1 | sed -n 's/^.*src \([0-9.]*\) .*$/\1/p')
SERVER_PUBLIC_IP=$(curl -s ifconfig.me)
REPLACE_MASTER_KEY=$(tr -dc A-Za-z0-9 </dev/urandom | head -c 30 ; echo '')
EMAIL="fake@email.com"
run it.
That's it?