Try this
Also renamed some variables so I could follow
Option Explicit
Sub CommandButton1_Click()
' Change folder path as needed, keep the trailing backslash
Const sFolder = "C:\Users\Daddy\Downloads\" ' back slash !!! <<<<<<<<<<<<<<<
Dim sFile As String
Dim mstWS As Worksheet
Dim srcWB As Workbook
Dim srcWS As Worksheet
Dim t As Long, s As Long, srcNextRow As Long
Application.ScreenUpdating = False
' Target sheet
Set mstWS = ThisWorkbook.Worksheets("Sheet1") ' or use ActiveSheet
' First available target row
t = mstWS.Range("A" & mstWS.Rows.Count).End(xlUp).Row
' Get first Excel filename in the folder
sFile = Dir(sFolder & "*.xls*")
' Loop through the files
Do While sFile <> ""
' Open source workbook
Set srcWB = Workbooks.Open(sFolder & sFile)
If Not srcWB Is ThisWorkbook Then ' don't use this WB <<<<<<<<<<<<<<<<
' Refer to the first sheet
Set srcWS = srcWB.Worksheets(1)
' Get the last used row
srcNextRow = srcWS.Range("A" & srcWS.Rows.Count).End(xlUp).Row + 1
' Copy range
srcWS.Range("A2:Z" & srcNextRow).Copy Destination:=mstWS.Range("A" & t)
' Increment target row
t = t + srcNextRow - 2 ' <<<<<<<<<<<<<<<<< is this what you wanted
' Turn off clipboard
Application.CutCopyMode = False
' Close source workbook
srcWB.Close SaveChanges:=False
End If
' Get next filename
sFile = Dir
Loop
Application.ScreenUpdating = True
MsgBox "Done"
End Sub