tryin to get a form text field to update a diff field as well?

[mrbeepa]

I have a form for sales people to input their installations. one field is the
install date. When this is entered in I would like not only for that to be
entered into the table but for it to also take that date and format it into a
week number and put that information in another column in the table. I tried
to do this in the table itself and was told that it should be done through a
form or a query.
I tried using the afterUpdate property but haven't figured out how to do
that with expression builder and although I am very familiar with many
languages vb is not one and I do not know what is being looked for in the
code view. I assume you would create a function but even that I do not
remember the correct syntax.

Any help would be appreciated, either doing it using the expression builder
or the code editor. Thank you muchly!

 

[mrbeepa]

Thank you David_Beginner that does help resolve one of my problems Much
appreciated!