how to specify data file in adobe live cycle designer?

I am following the documentation tutorials point at which I am stuck this tutorial has given how to attach the pdf with the data file in preview mode. I have successfully done it but , I don't know how to do it for the time when we are going to open pdf. I mean whenever I open the generated pdf in adobe acrobat independently the data doesn't appear in the fields. Please guide how to do it.

The tutorial points towards using AEM Designer for previewing your PDF design with a sample data file. You can only do this in the Preview tab of AEM Designer. Once you finalize the PDF and open it up with Adobe Acrobat, it will show you the finalized PDF and will NOT have the sample data that you used for testing purposes.

If you are looking to import data into the finalized PDF, use Acrobat Pro:

• Open the PDF form into which you want to import data. Choose Tools > Prepare Form.
• Choose More > Import Data. In the Select File Containing Form Data dialog box, select a format in File Of Type corresponding to the data file you want to import.

Reference link for the operation Above: https://helpx.adobe.com/ca/acrobat/using/collecting-pdf-form-data.html