Using data that is stored in files such as an Excel spreadsheet or text file to create labels is called using an External Data Source.  There is information in the Help documentation in Wasp Labeler that gives step-by-step instructions on how to use an External Data Source.

Go to the Data menu and select External Data Source Wizard. Click the Help button in the lower left corner for detailed instructions on how to use the wizard to select your external file, and the data columns within the file to which you want to link your label objects.