Create range based on sheet index in VBA

Question

I am trying to create a range by using the Sheet index, but every option I intend to use always retrieves an error, is this even possible?

Here my example

Dim columnsRange As Range
columnsRange = ThisWorkbook.Sheets(1).Range("D1:N1")

I use a similar sentence when trying to get the number of used columns:

var = ThisWorkbook.Sheets(1).Cells(1, Columns.Count).End(xlToLeft).Column