Creating the Traffic Manager profile using PowerShell is slightly different than the portal, because with PowerShell you need to specify some additional configurations. You can do so by running the following cmdlet:

New-AzureRmTrafficManagerProfile -Name PacktProfile -ResourceGroupName PacktPub -TrafficRoutingMethod Performance -RelativeDnsName Packt -Ttl 30 -MonitorProtocol HTTP -MonitorPort 80 -MonitorPath "/"

You can see that there is Name and RelativeDnsName. The difference between them is that the Name is the displayed name for the Traffic Manager, but RelatvieDnsName is the portion of the hostname that makes the following FQDN: http://packt.trafficmanager.net

With respect to the other parameters, you saw them earlier in the Traffic Manager configurations section.