You are not understanding the problem you need to parse the string (e.g. "1,2,3,4-8") into an array and this is not simplke if you are not a coder.

This is just off the top of my head but might get you on the right track.

Sub getSelection()
Dim L As Long
Dim rayFixed() As Variant
Dim sldR As SlideRange
Dim strInput As String
Dim raySlides() As Long
strInput = InputBox("Input slides to select")
rayFixed = getArray(strInput)
ReDim raySlides(0 To UBound(rayFixed))
For L = 0 To UBound(rayFixed)
raySlides(L) = CLng(rayFixed(L))
Next L
ActiveWindow.ViewType = ppViewSlideSorter
Set sldR = ActivePresentation.Slides.Range(raySlides)
sldR.Select ' or copy etc
End Sub

Function getArray(strIn As String) As Variant
Dim rayNum() As String
Dim rayTemp() As String
Dim L As Long
Dim X As Long
Dim rayCorrect() As Variant
rayNum = Split(strIn, ",")
ReDim rayCorrect(0 To 0)
For L = 0 To UBound(rayNum)
'deal with x-y type
If InStr(1, rayNum(L), "-") > 0 Then
rayTemp = Split(rayNum(L), "-")
For X = rayTemp(0) To rayTemp(1)
rayCorrect(UBound(rayCorrect)) = CStr(X)
ReDim Preserve rayCorrect(0 To UBound(rayCorrect) + 1)
Next X
Else
'deal with x,y type
rayCorrect(UBound(rayCorrect)) = rayNum(L)
ReDim Preserve rayCorrect(0 To UBound(rayCorrect) + 1)
End If
Next
'remove top blank value
ReDim Preserve rayCorrect(0 To UBound(rayCorrect) - 1)
getArray = rayCorrect
End Function