The following are instructions I've been using successfully that I found in an old thread. This was posted before Data Bridge existed, but I imagine it should still work:
• 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 current 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.
Hope this helps.