UserForm - Two Button - Start and Pause button

I have restructured the logic a bit. You just need one button which acts as the start and pause / resume. The code for your userform will be as follows:
It is all contained in the attached workbook.

Option Explicit
Dim NextRow As Long
Dim FirstRow As Long
Dim PausePressed As Boolean
Dim nrRows As Long

Private Sub cmdPauseResume_Click()
    If NextRow = 0 Then
        PausePressed = False
        NextRow = FirstRow
        cmdPauseResume.Caption = "Pause"
        Call ImportData
    Else
        PausePressed = Not PausePressed
        cmdPauseResume.Enabled = False
        If Not PausePressed Then
            cmdPauseResume.Caption = "Pause"
            cmdPauseResume.Enabled = True
            Call ImportData
        End If
    End If
End Sub

Public Sub ImportData()
    
    Do While NextRow <= nrRows
        If PausePressed And NextRow > 1000 And NextRow Mod 100 = 0 Then
            Exit Do
        End If
        '  Your code for importing row NextRow
        NextRow = NextRow + 1
        If NextRow Mod 10 = 0 Then
            lblProgress.Caption = "Processing row " & NextRow & " of " & nrRows
        End If
        DoEvents
    Loop
    If NextRow > nrRows Then
        MsgBox "All done"
    Else
        cmdPauseResume.Caption = "Resume"
        cmdPauseResume.Enabled = True
        MsgBox "You told me to take a rest"
    End If
End Sub

Private Sub UserForm_Initialize()
    nrRows = 100000  '  Your code for working out how many rows   'ActiveWorkbook.Sheets("Sheet3").UsedRange.Rows.Count
    FirstRow = 1 ' Your code for working out where to start  'Cells(Sheets("Sheet").Rows.Count, "C").End(xlUp).Row - 3
    NextRow = 0
    cmdPauseResume.Caption = "Start"
End Sub

thank you so much for your help