Looping a 'fill down'

Hi all - sorry, I'm very new to all of this. I want to have a program which will highlight the next 1000 cells in a column, 'fill down' and then move to the bottom of the filled column (does it do this already?) and then move up three cells, before highlighting the next 1000 and filling down again. I can record the first fill but don't know how to change it to a loop. Sorry if this sounds very confusing!

Thanks for any help!

Without the loop, it looks like:

Sub Macro1()
'
' Macro1 Macro
'

'
    ActiveCell.Range("A1:A1008").Select
    Selection.FillDown
    ActiveCell.Offset(1005, 0).Range("A1").Select

End Sub