save data from form to table

[Bilal]

i got a form with three normal fields where i add data i then have two auto number fields i.e. SupplierID and PersonID the supplierID works fine, i can add a new record and click save and it will save the data in the suppliers table.
The problem is with my PersonID field, i need it to retrieve the data from my subform and firstly display in the field on my main form and secondly, when i click save it should save save the number that is displayed into my Suppliers table, im maybe looking in the wrong place to change all this but if anyone could help that would be brilliant if you need to see my DB just let me know
Bilal

 

[Bilal]

Subforms have multiple records. What record would you choose and why duplicate the data?

if you take a quick look at my Db's suppliers form which is atached, you will understand why i want the person ID to save in to tables, one table as a primary and the other as a foreign key because the PersonID field will be the one field that links tblPerson and tblSupplier.
im just unsure of what code il need to put and also where i put it.