What do you mean by "difficulty"?
It should be relatively straight forward, using the raw analog input (i.e. Local:2:I.Ch0Data) "wired" into the PV/Input of the scale block, then the final resulting tag (i.e. Tank2Temp) "wired" to the output.
You set up the scaling by clicking the setup box and setting your device input range (0-10, 4-20, 0-20, 0-32767, whatever) and your operating Engineering units range (0-300 'degrees'). You can also use tags or constant input references wired to the SCL block if you expose the pins. Make sure the data types you are using are REAL.
Does this help?