Using a variable to define a range in VBA

Hi,

I have 2 questions:

Question 1

I have a sheet with cols A:K, row 1 is the headings. Cell N1 is a calculation to return how many rows there are is a different part of the work book.

for this assume that N1=100

In A2:K2 I have formulea that need copied down 100 rows (given that N1=100)

I have tried the following code:

Sub CD6007()
'
' CD6007 Macro
'
'
    Dim rows As Integer
    Set rows = Cells(1, 13).Value
    Range("A2:K2").Select
    Selection.AutoFill Destination:=Range("B2:K" & rows), Type:=xlFillDefault
    
End Sub

But this is not working.

Please can someone help me, i cannot work out what is wrong with it!

Question 2

I have a column that is populated with different text values and some blanks, what VBA would i use to search this column and replace all blank cells with the word "BLANK"

I have tried

Sub BLANK()

        Dim rows As Integer
        Set rows = Cells(1, 13).Value
	Range("D1:D" & rows).SpecialCells(xlCellTypeBlanks) = "Blank"

End Sub

Thanks very much in advance

P.S. I only started looking at VBA recently so i apologize if these are simple/stupid questions..