Starting a Service (vncserver) at boot

RedHat 8.0

can start the service from the command line but I need to start it at boot
time before anyone logs in.

There must be a file somewhere (like a .conf) that will allow me to add the
commands required. As usual, if I am going strange here (as in "don't do
this in the real world"), please let me know. However, at the moment, this
is for demonstration (not real world) purposes only.