After you have installed the DYMO LabelWriter you will need to set it up with the proper label settings
Right click on your Printer icon in your Printer and Faxes directory
Go to the advanced tab and click the Printing Defults button

Change the Orientation to Landscape

Click the Advanced button
Set your paper size to 30256 Shipping

Click the OK button
Click the Apply button then click OK to exit the Printing Defults window
Click the Apply button then click OK to exit your printer Properties window