The only roll that can be used with the Datamax W1110, 1E35, 1E40, 1E41, or 1E45 printer is item number 6WB-F in the Pitney Bowes Online Shop. However, "6WB-F" does not appear anywhere on the roll itself.
Position the label roll as shown here. The roll should feed from the top so that the adhesive labels face up.
Feed the end of the label roll under the brackets.
Once the label roll has been positioned, close the cover and press the button to feed the label.