Using the find In VBA

I am trying to write a macro that will deduct an item from my stock (which is housed in a different workbook) when I hit the complete button. My thoughts were to use the find function, activate the cell, and then subtract the quantity from the active cell. I am just starting with the macro, but I am running into an object error with my find.

Sub Deduct()

Dim C As String

'Deduct the Quantity from Stock

Workbooks.Open "C:\Users\furnd\Desktop\Test Deduct.xlsm"

With Workbooks("Test Deduct.xlsm").Sheets("Sheet1").Range("A1:A2000")

Set C = .Find(What:="A1").Value

End With

Workbooks("Test Deduct.xlsm").Activate

Sheets("Sheet1").Select

C.Offset(0, 1).Select

End Sub