The administration and maintenance of Microsoft Exchange Server to ensure secure, reliable, and efficient email and collaboration services across an organization.
Run setup and install Exchange meeting all the requriements:
https://learn.microsoft.com/en-us/exchange/exchange-2013-prerequisites-exchange-2013-help
Add the server to any existing send connector if desired.
Set any custom receive connector following what you have set for the other servers
thats it really.
Doesnt sound its a member of a DAG.
Why the need to add another server?