Setting up Communigate server

[stioanid]

I am new to Communigate and I am trying to setup for our mail services and honestly I don't know where to start from.
I have the guide but it isn't very helpfull.
My situation is the following.

I have setup the local network with all linux machines and some window machines.
All users are authenticating through LDAP & Samba .
I have installed communigate in a Ubuntu 8.04 Server.

My local domain is example.com.

Now I wan't to serve two domains with mail services.
example1.com and example2.com.

So my question is the following:
I started configuring Communigate by accessing the webpage http://myserverhostname:8010.
So for start I went to the Settings tab and inputed example.com as my main domain and the two domains (example1.com and example2.com) as secondary domains.

Now the guide was pointing out the following:


If your Server should serve several domain names, enter the additional domain names as Main Domain Aliases (if those domain names should be "mapped" to the Main Domain), or create additional ("secondary") Domains.
Sample configuration:Your Server should serve the company.com and client1.com domains. These domain names have their DNS MX-records and SIP SRV-records pointing to server.company.com and server.client1.com A-records, and these A-records point to IP address(es) assigned to your CommuniGate Pro Server system.

• set company.com as the Main Domain Name.
• open the Domains page, find the company.com record and click on its Settings link to open the company.com Domain Settings page. Scroll it down to find the Domain Aliases fields.
• enter server.company.com into an empty Aliases field, and click the Update button.
• open the Domains page. Enter client1.com into the text field and click the Create Domain button.
• the client1.com record should appear in the list; click its Settings link to open the client1.com Domain Settings page. Scroll it down to find the Domain Aliases fields.
• enter server.client1.com into an empty Aliases field, and click the Update button.

So my question is should I have added as secondary domain or as Aliases nad what is the difference between them?

Thanks in advance for any help provided.