How To Hide/Unhide sheets based on a button click

One way

For Oval 1 macro

Const shCover As String = "Cover"
Sub Case1()
 Dim ws As Worksheet
 Application.ScreenUpdating = False
 For Each ws In Worksheets
    If ws.Name <> shCover Then
        If ws.Name Like "Case 1*" Then
            ws.Visible = xlSheetVisible
        Else
            ws.Visible = xlSheetVeryHidden
        End If
    End If
 Next
 Worksheets(shCover).Select
 Application.ScreenUpdating = True
End Sub

For Oval 2 macro

Sub Case2()
 Dim ws As Worksheet
 Application.ScreenUpdating = False
 For Each ws In Worksheets
    If ws.Name <> shCover Then
        If ws.Name Like "Case 2*" Then
            ws.Visible = xlSheetVisible
        Else
            ws.Visible = xlSheetVeryHidden
        End If
    End If
 Next
 Worksheets(shCover).Select
 Application.ScreenUpdating = True
End Sub