Something like the following, change the SlideNumber from 10 to whichever slide you need.

Dim slideNumber As Integer
Dim maxSlideNumber As Integer
Dim ssw As SlideShowWindow

Set ssw = Application.SlideShowWindows(1)
slideNumber = 10

maxSlideNumber = ssw.Presentation.Slides.Count
If slideNumber > 0 And slideNumber <= maxSlideNumber Then
ssw.View.gotoSlide slideNumber
Else
MsgBox "Slide number invalid - '" & slideNumber & "'."
End If