From the helper under step one, click Create to create the main document. Then click Form Letters. At choice number 2, click Get Data. If you intend to create a new data set, click Create Data Source. You will get a dialog box and a data source tool bar.
Word proposes a set of data field names.
There are more than you need, so you probably will want to remove some of them. To remove a field name you do not need, highlight it and click Remove Field Name. You may want to add a field name of your own. You may want to change the order in which you will enter data. If so, highlight a field name and move it to the desired location using the Move arrow keys on the right side of the dialog box.