The Mac agent is a self-contained .dmg file stored on the core server under http://coreservername/ldlogon/mac/youragentname.dmg. There are two ways to install the agent. The first method is via a push from the core server. This is the easiest method as long as you have an admin account on the Mac and if the Mac has SSH enabled. If you don't have an admin account or if you don't have SSH access, you'll need to manually download the agent from the URL, email it, put it on a zip drive, etc. and then manually install it.
If you're setting up your Mac for the first time, to enable SSH access, all you need to do is Enable the Remote Login service under System Preferences > Sharing. Then setup an admin account and make note of the actual account name, not the full name.
On your Core Server, select Configure from the menu at the top, select Services and then click on the Scheduler tab. Hit the Change Login button and put the admin account and password into the Alternate Credentials section. Save and restart the inventory service.
You can now perform an unmanaged device discovery scan to find your machines, create a task from your agent configuration and drag the machine from UDD to the task and push out the agent.
I've got an old powerpoint with embedded videos that you can watch. See slide 15: Dropbox - LANDesk_MacAdmins2013.pptx. It's a bit outdated, but should get you up and running.