Populate table fields from text box

[captnk]

I have a text box on a form,into which I enter a number.
(The form only displays 1 item at at a time from a table with multiple items.)

That automatically poulates the equivalent item table!field with that number.
However I want it to populate that table!field for ALL ITEMS in that table,from the one text box entry

Any suggestions/ideas pls

Regards

 

[captnk]

Tks Pat
As far as I can see the field I want to populate is in table that the main form is based on

The form comprises the main and a subform.
However the main form is derived from the table am trying to populate.

I suspect that u r probably on the right track,so i will have a closer look at the supporting tables and joins
Regards