BE2012 - Agent for Applications and Databases - how to install

We just purchased some additional BE 2012 Agents (3x Agent for Applications and Databases) for our existing BE2012 environment and I cannot figureout how to install these out to some of our already Agent for Windows managed servers.

We have 1 media server and 6 agent managed servers. I need to add the new agent for Apps and DB's to some of the agent managed servers.

I have already added the license to the media server and it shows as installed / activted.

Can someone help on this?

Thanks