No, there is not a tutorial for creating a form using Form Builder and suing DataAssist to insert the form information to a database, but it is a fairly easy thing to accomplish.
Just make sure the forms action is set to post to itself and that the forms method is set to POST.
then go to the Server Behaviors panel (Window -> Server Behaviors).
Click the plus button and select WebAssist -> DataAssist -> Insert Record -> Single Record Insert
Set the trigger to Use either any form post or currant page submit.
Choose your database connection and the table the data will be inserted to.
On the second page of the Insert Record Wizard, select each column from your database, then click the lightning bolt and select the corresponding form field.