Righ click the field that you want to have required and click Form Field
Properties. Click on the Validationbutton at the bottom. You can then select
it to be required form there.
Either double click on the field or go to properties, then
click on the validate button. you have many options in
that window, the easiest one to use I think is the Data
Length option, you can enter the minimum and maximum
amount of chrs. you want the user to enter.
