Declaring Variables in Excel VBA

[andy_uk]

Hi all, dunno the correct terminology (it's not in Lesson 1, Annie!), so apologies if the title's misleading. I've kludged for years, but I am TRYING to learn properly now. Basically I have this :

Sub Enter_Name()
x = Application.InputBox("Enter name.")
n = WorksheetFunction.Find(" ", x) - 1
Range("H1") = Left(x, n)
Range("H2") = WorksheetFunction.Substitute(x, Range("H1") & " ", "")
End Sub

, which works fine.

(It's best if I ask one thing at a time, so I'll start with) should I/do I really need to prefix with "Dim x As blah, n As ???", or whatever the heck it's called?

TIA,
Andy