updatable inventory tracker

Hi all,

I am working on an excel sheet that allows me to update inventory quantities and reorder amounts, but i am very new to VBA so i am stuck again.

I am attaching my file so anyone who is kind enough to help can better see visualize what i describe.

I have a drop down list in B3 that is a list of the range from B8:B45. Next to the drop down list, i have a couple of cells for adding or subtracting inventory quantity that when i enter a number i hope to have the following happen:

1. update the values in the range of M8:M45 corresponding to whichever item is selected from the drop down list
2. automatically clear the number entered in the cells for adding or subtracting inventory so that another item from the drop down list can be selected and a new number can be entered without affecting the previous selection

Any help would or advise to lead me in the right direction would be fantastic!