Professional Services should be included in the purchase of a new filer and can help. The general steps are 1) set up SnapMirrors, 2) set up final resync after fencing i/o from source (old filer), 3) cut over LUNs to new filer, 4) online volumes and LUNs and present to host, 5) resume normal operations on new filer.
Is there anything specific you need? You can always create a test LUN and test the procedure for yourself.