DNS records for second email domain

I need someone to write all DNS records (not change dns settings) but provide a list of all new DNS records to add.

I will add 2nd domain to existing email server postfix admin

Write the new DNS records based upon the following info:

Current email domain =. smtp.example.com
Current IP = 212.107.58.115

New / second email domain =. smtp.testing.com
Same IP = 212.107.58.115