VBA Multiply Function & Sub Procedure to Show Result

I have Created a Function to Multiply & a Sub to Show Result In MsgBox

Function MultiplyTwo(N1, N2)
MultiplyTwo = N1 * N2
End Function

Sub ShowResult()
Dim N1 As Double, N2 As Double
Dim Result As Double
N1 = 132
N2 = 456
Result = MultiplyTwo(N1, N2)
MsgBox Result
End Sub

It works fine when I State N1 as 132 & N2 as 456.

However i want N1 & N2 to be extracted from the Worksheet named Prices in a Workbook Named "Basic Beginers Codes".

Where N1 lies in Cell A2 & N2 Lies in Cell A3.

What changes should I make to the code?