Postfix - Mysql - howto MultipleDomain?

[Maurizio Caloro]

Hello

Here with me Postfix+Dovecot+Mysql Installation on Debian 10 i am 
running now meny years with
a setup from one Domain. Now i need to add a second Domain:
    ->Example1.ch
    ->Example2.ch
i was trying and adding now this second Domain to MYSQL and Postfix, but 
i see this arnt running.

So please exist any little howto, to add multiple Domains to 
Postfix+Mysql setup.
meny thanks for possible help

thanks