Linking Domain names to Websites (Cheapdomains, Azure)

Hi all,

I have run into an issue that I just can't seem to figure out. I will explain in detail below.
Thanks in advance for any productive suggestions or tips.

I am currently working for a company that have 5 existing websites. They changed the systems and now all the website files exist on cloud server hosted by Microsoft Azure.
The domain names were bought from www.cheapdomains.com.au. I have set up the A records on the registrars account and added the server names.
Now, I am told that I need to set up zones and www A records with the DNS management service.
These were my only instructions on how to accomplish this.

No they are Windows 2012 r2 Servers. So you need to start the DNS Management Service and create the zones.

Primary Zone for DLMVM1 and Secondary Zone DLMVM2.

You will also need to create www A records for the domains.

Then create websites in IIS on DLMVM1 including the http bindings.

Each 5 websites already have domain names associated with them.
I was told that you could link more domain names to certain websites. I am very new to all this so any and all information of relevance would be of help.

Thanks in advance