There is not a video tutorial for this.
Create a recordset for the parent list
Create a second recordset for the child list
add the parent and child select lists to the page.
Set the Parent list to populate using the recordset, set the value to the ID and the label to the name column
In the server behaviors panel, click plus and select web assist -> Dynamic Dropdowns -> Create Dynamic array.
for the recordset, select the cheekily recordset.
Set the parent ID to the relational column that relates to the parent.
Set the Child ID to the ID column and the Child Label to the Child name column
in design view, select the parent list and then go to the behaviors tab. click plus and select Webassist -> Dynamic Drop Downs -> Populate list from array.
Set the parent to the parent and child to the child, make sure the trigger action is set to onChange