Issue adding second RDSH 2012 server

Hello,

 My colleague setup RDS 2012 on a single server, consisting of an RDSH, Web Gateway and licensing server. I've tried to add a second server within the setup, but whenever I open licensing diagnostics it tells me that the second server is unlicensed and the second server does not appear to be part of the same RDS collection as the first server. However, the second server can see the first as a licensing server within the RDS management console.

What's the correct procedure for adding a second RDSH to an existing RDS 2012 collection?

Thanks

IT Support/Everything