On this page of the wizard, you'll intialize your printer to print an alignment test sheet that you can use to measure how far off your printer's alignment is. Once you click the "Next" button, the wizard will print the alignment test sheet on the printer you've chosen on this page.
Printer: Choose the printer you're testing alignment for. Make sure the printer is turned on and hooked up to your computer before you click the "Next" button.
Paper Bin: Choose the paper bin that you want your printer to use for printing the alignment test page.
Properties: Click this button to launch your printer's custom properties dialog, which lets you set features unique to your printer, such as print quality, ICM management, etc. The alignment test sheet is a simple black-and-white printout, so it's unlikely that you'll need to make any adjustments here.
Number of Copies: Decide how many copies of the alignment test sheet you want to print. Just printing one will help, but printing multiple copies and comparing them will help you determine whether your printer's alignment is off by a consistent amount or whether it varies from print job to print job.
If your alignment does vary from sheet to sheet, it's difficult to pick a precise alignment amount that will work. You might try picking average values and then using the stretch settings on the Printer Alignment dialog (click the "Alignment" button on the Print dialog to get to the Printer Alignment dialog).
Paper Size: Choose the paper size that you'll be printing your alignment test sheet on.
One more note on paper alignment: be sure your paper fits snugly in the paper tray, and there's no space between the edges of the paper and the tray's paper guides. If your paper has room to slide around inside the paper tray, there's a good chance that this will cause alignment errors on a large variety of printer models.