If you can, it's a good idea to let JMP do the work for you - Generally you only need to do things 'by hand' once, then use the code that JMP generates automatically.
In you case, if you do 'Tables > Stack':
hitting 'OK' gives a new table that has a saved script called 'Source'. If you right-click on the associated green 'run' icon, you can select 'Edit', which will give you this script:
Data Table( "FINAL.jmp" ) << Stack(
columns(
:Name( "2010;PinShort@CLK" ),
:Name( "2011;PinShort@IO" ),
:Name( "2012;PinShort@VDD" ),
:Name( "2013;PinShort@LA" ),
:Name( "2014;PinShort@LB" ),
:Name( "2030;PinOpen@CLK" ),
:Name( "2031;PinOpen@IO" ),
:Name( "2032;PinOpen@VDD" ),
:Name( "2033;PinOpen@LA" ),
:Name( "2034;PinOpen@LB" ),
:Name( "2200;Ana_Idd_noClock@VDD" ),
:Name( "2360;Dig_ATE_FUN_00_001_Authenticate" ),
:Name( "2361;Dig_ATE_FUN_00_003_DisableReset" ),
:Name( "2380;Dig_ATE_FUN_00_004_GetVersion" ),
:Name( "2440;SyncPulse_and_capResponse_0x90" ),
:Name( "2441;Ana_Pads_ATE_VOL_0uA@IO" ),
:Name( "2442;Ana_Pads_ATE_VOH_0uA@IO" ),
:Name( "2443;Ana_Pads_ATE_VOL_0uA_IDD@VDD" ),
:Name( "2444;Ana_Pads_ATE_VOL_0uA_Rcont_GND@VSS" )
),
Source Label Column( "Label" ),
Stacked Data Column( "Data" )
)
You can make this script smarter, but if you are just adding new rows it will work fine (so long as the columns it needs are still in the source table).