To specify the paper size, resolution, PDF settings, etc., click Settings..., and then set each item in the Settings (Custom Scan) dialog.
Once settings are made in the Settings dialog, the same settings can be used for scanning from the next time.
In the Settings (Custom Scan) dialog, specify image processing settings such as slant correction, set where to save the scanned images, and more, as needed.
After adjusting the settings as desired, click OK.