UPDATE 11:00 30/05/2019
I have ran the command
openssl req -x509 -newkey rsa:4096 -days 3650
but it just prints the key inside the terminal window and doesn't output to a file.
I added -noout to the command but the file has saved it saved itself at ~privkey.pem and not in the direcory I set in the openssl.cnf file /home/will/demoCA.