Call Dropping at 30 seconds when placed on hold

This has been done on many other blogs around the place, but I ALWAYS seem to get the first step wrong.

When trying to change the following values:
-RTCPActiveCalls
-RTCPCallsOnHold
-EnableSessionTimer

First step is "New-CsTrunkConfiguration", NOT "Set-CsTrunkConfiguration"

Trying to run the "Set-CsTrunkConfiguration" first will result in errors like below