In Form Builder, you can set up validation by setting up the type of form element it is, and you can further modify the validation. If you choose edit next to the Choose a form section and then select the group you want to modify and click edit, you can check individual form elements to validate. To show the form if you're not logged in, you would have to check if the user is logged in and then have the code written out if the user is not, otherwise skip that code.