1. Consider making it a required field in the Validation options.
2. Make it (your 2nd and 3rd field) an auto-enter field, make sure the option "Do Not Replace Existing" is checked.
A formula like this should do what you want, post back if you have any problems with it. It should fill in the field with the first item on that value list the first time Field1Name is altered...and not again after that.
Let ( [ f1 = Field1Name ]; GetValue ( ValueListItems ( Get ( FileName ) ; "ValueListName" ); 1 ) )
Replace Field1Name with your actual field name.
Replace "ValueListName" with your actual Value List name in quotes.
I haven't actually tested it...typing off the top of my head...you may need to make a tweak or two.
Well, it didn't work, I don't know if my message was clear enough, whenever the user select item from the fist list the second list drop the menu for him to select of it, but the user sometimes forget to select item from the second menu, what I want to do is to set the field text to the first item from the list with dropping down the list menu, therefore regardless the use select or forgot I should have a value in the field.
Where the formula should be??? i have tried several thing but didn't work for me