Auto Fill Columns when adding using New from Dropdown

[Manish_Jain11]

I have 2 Tables - Orders and Products .

In Orders, I have a column for Product which is referenced to Product Table. So When adding , I use the dropdown to add the Product if not listed , user can use the New from the dropdown . All work ok but I have a column called First Order in the product table which is Referenced to Orders Table, So when a user creates a new order using the Product dropdown when creating an order, It should autofill the current orders ID in the First Order Column of the Products Table. How is it possible ?

Also , I dont see the New button in any dropdowns when editing exisiting records. What do I do to see the new button link when editing the record too just like when creating a new record.