Need help with subtracting and copyng record into another table with a click

[zyper]

Hello all!

I'm a newbie so I will need a lot of help. I hope you will understand my problem. I am bookkeping and storing spare parts in my warehouse.
I have 2 tables

1. Warehouse
2. Bookkeeping

So i have a warehouse of spare parts and what i wanna do is to create a form where i can insert ID of spare part, Who took the spare part and how many peaces did he take.
I want the button "ok" to:

1. subtract(Warehouse.PeacesInStock -Bookkeeping.HowManyPeaces) and write the new number in Warehouse
   
2. Copy the record into bookkeeping

Tables look like this
Warehouse:
ID
nameofproduct
Location
Details
PictureLink
Price
Stock

Bookkeeping
ID
nameofproduct
location
details
price
NameOfThePersonWhoTookTheProduct
HowManyPeacesDidHeTake
When

So as you see I dont want to copy whole record i need to copy just a few atributes the other ones i want to insert with form.