Open the database. The database window is the thing that shows up with
Tables, Queries, etc. on the left side, and the actual objects on the right.
If you click Forms you will see a list of the forms in your database. Open
your form in design view, then click View >> Properties. This opens what is
known as the form's Property Sheet. The Property sheet for a control such
as a text box may be opened similarly, except you first need to click the
control to select it. For now, just look at the form's Property Sheet.
Click the Events tab. Click Current, and click the three dots on the right.
Click Code Builder, OK. The VBA editor should open, with something like
this:
Private Sub Form_Current()
End Sub
The cursor should be blinking between those two lines. Enter the code
there.
If I once knew what exactly the Me stands for, I have forgotten. When you
type Me and a dot you are then able to enter one of the form's properties.
Fields and controls are considered properties of the form. Me.CheckBoxName
refers to the text box. SomeField in my suggested code would be your
DeliveryDate field. Not IsNull(Me.DeliveryDate) evaluates to True if
DeliveryDate is not null (i.e. contains a value). In that case
Me.YourCheckBox = True; otherwise it is False.
Again, no need to store Closed. The presence of a delivery date already
indicates the record is closed.