For non-object return types, you have to assign the value to the name of your function, like this:
Public Function test() As Integer
test = 1
End Function
Example usage:
Dim i As Integer
i = test()
If the function returns an Object type, then you must use the Set keyword like this:
Public Function testRange() As Range
Set testRange = Range("A1")
End Function
Example usage:
Dim r As Range
Set r = testRange()
Note that assigning a return value to the function name does not terminate the execution of your function. If you want to exit the function, then you need to explicitly say Exit Function. For example:
Function test(ByVal justReturnOne As Boolean) As Integer
If justReturnOne Then
test = 1
Exit Function
End If
'more code...
test = 2
End Function
Documentation: http://msdn.microsoft.com/en-us/library/office/gg264233%28v=office.14%29.aspx