Have you applied the correct MemReadFunction normal 3 for a read on Modbus and the correct MemAdress according the Register-specs of the device.
The Video was dealing with a serial device, but you use tcp/ip. If the settings are not ok, you get nothing = 0.0.
--- edit: Install the RTTI components, put 3 TIPropertygrid on your form an connect on to the tcp_UDP_port, one to the proctocol and one to the Tag.
If you start, you can see the information like in the Objectinspector and look from the tcp_port upgoing if the any errormessage.
The Port must be Active and you should see TXBytes and RXBytes raising.
On the protocoldriver you see normal the AvgTagUpadateTime as a value not Zero
In the PLCTag, Comm* should be ok and the Last*Sync should ne ioOk