XL 2019 mettre 2 worksheet différents sur la même feuille

Bonjour à tous,

Sauriez-vous comment je peux intégrer 2 worksheet dans une même feuille ?

1ière macro
Private Sub Worksheet_SelectionChange(ByVal Target As Range)
Dim isect, Z$, plage
If Target.Count = 1 Then
Z = Target.Value
plage = "h18"
Set isect = Application.Intersect(Target, Range(plage))
If Not isect Is Nothing Then
Target.Value = IIf(Z = "", "ü", "")
End If
plage = "j18"
Set isect = Application.Intersect(Target, Range(plage))
If Not isect Is Nothing Then
Target.Value = IIf(Z = "", "ü", "")
End If
plage = "Q24:Q43"
Set isect = Application.Intersect(Target, Range(plage))
If Not isect Is Nothing Then
Target.Value = IIf(Z = "", "ü", "")
End If
plage = "R24:R43"
Set isect = Application.Intersect(Target, Range(plage))
If Not isect Is Nothing Then
Target.Value = IIf(Z = "", "ü", "")
End If
plage = "S24:S43"
Set isect = Application.Intersect(Target, Range(plage))
If Not isect Is Nothing Then
Target.Value = IIf(Z = "", "ü", "")
End If
plage = "Q45:Q48"
Set isect = Application.Intersect(Target, Range(plage))
If Not isect Is Nothing Then
Target.Value = IIf(Z = "", "ü", "")
End If
plage = "R45:R48"
Set isect = Application.Intersect(Target, Range(plage))
If Not isect Is Nothing Then
Target.Value = IIf(Z = "", "ü", "")
End If
plage = "S45:S48"
Set isect = Application.Intersect(Target, Range(plage))
If Not isect Is Nothing Then
Target.Value = IIf(Z = "", "ü", "")
End If

End If
End Sub

2ième macro
Private Sub Worksheet_Change(ByVal Target As Excel.Range)
On Error GoTo line

If Target.Address = Range("d19").Address And Range("d19").Value > 10 Then

Dim I
For I = 1 To 3 ' Loop 3 times.
PlaySound ThisWorkbook.Path & "\0257", 0, 1
MsgBox "Attention valeur hors tolérance"
Next I

End If

line:
Exit Sub
End Sub

Je bute depuis plusieurs heures même en allant sur les forums (sachant que je suis pas expert dans les macros)

Merci d'avance pour votre aide^^