Inventory transaction table - set up

Hi,
I am a new user of Access 2007. I am creating a database to track inventory
quantities by locations. I have a Products table and a Locations table, and I
am wondering what is the best way to set up a Transactions table. We have
three types of transactions:
1. Move products from one location to another.
2. Introduce new products to a location.
3. Deplete products from locations.
We would like to keep a record of transactions, by transaction ID and date.
But the more important function will be to report on current Product
quantities by Location.

What fields should I include in the Transactions table, and with what
relationship types to the other two tables? Do I need more than one
Transaction table? Should I put Add and Remove quantities in separate columns?

Thanks for your help!