1) On the manage pages tab, click the configure filed settings option to set up the validation for the password
2) you can change the validation settings after the pages are created by editing the spry validation settings and the Server Validation settings.
to change spry validation settings: Select the form element in design view, then click the blue bounding box that surounds the form element. This will show the spry validation settings in the property inspector.
to change server validation settings, go to the server behaviors tab and double click the Server Validations server behavior.