config to setup local fqdn webserver

[Sid]

Hi,
I installed vestacp on my server, everything works perfactly, BUT with IP address.

This is a local server only for local network.
I have a single server with IP 192.168.0.2.
192.168.0.2 will be a web server, mail server and DNS server. Right now email works only with roundcube.
I want to assign fqdn
* "www.as.com" for my web UI1.
* "mail.as.com" for 192.168.0.2/webmail i.e email page.
and want want email server to work with ns outlook too.

can any one please help me out with the procedure.

Thanks