Extract Value to use in another field

Hi All,

New to this but just can't work out where I am going wrong with a simple extraction and then using the extracted value in another field.

Extracting a number from 'Transaction Number' element.

'Extract 'TextContent' on 'Transaction Number' into DataBindVariable $(TxnNumber) - DataDriven: [$(TxnNumber)]

Then want to enter this number into another field 'Transaction Number Filter Box'

Enter text '' in 'Transaction Number Filter Box' - DataDriven: [$(TxnNumber)]

I've followed this but still can't seem to get it to work.

Create an Extraction Step | Progress Test Studio (telerik.com)

Help!