r = Index \ NUM_COLS
    c = Index Mod NUM_COLS

Calculate index from row and column using:

    Index = r * NUM_COLS + c

Private Const NUM_ROWS = 10
Private Const NUM_COLS = 4
Private Const MAX_ROW = NUM_ROWS - 1
Private Const MAX_COL = NUM_COLS - 1

Private strings() As String

Private Sub Form_Load()
Const GAP = 60
Dim X As Single
Dim Y As Single
Dim wid As Single
Dim hgt As Single
Dim r As Integer
Dim c As Integer
Dim i As Integer

    ' Make a string array to match the TextBoxes.
    ReDim strings(0 To MAX_ROW, 0 To MAX_COL)

    ' Create and position the controls.
    X = Text1(0).Left
    Y = Text1(i).Top
    wid = Text1(i).Width
    hgt = Text1(i).Height

    ' Create the controls.
    For i = 1 To NUM_ROWS * NUM_COLS - 1
        Load Text1(i)
        If i Mod NUM_COLS = 0 Then
            ' Start a new row.
            X = Text1(0).Left
            Y = Y + hgt + GAP
        Else
            X = X + wid + GAP
        End If
        Text1(i).Move X, Y, wid, hgt
        Text1(i).Visible = True
        Text1(i).Text = i
    Next i

    Text1(0).Text = "0"
End Sub

' Update the corresponding string.
Private Sub Text1_Change(Index As Integer)
Dim r As Integer
Dim c As Integer

    r = Index \ NUM_COLS
    c = Index Mod NUM_COLS
    strings(r, c) = Text1(Index).Text
End Sub

' Change the color of the TextBox just to verify
' that our row and column calculations are right.
Private Sub Text1_Click(Index As Integer)
Dim r As Integer
Dim c As Integer

    r = Index \ NUM_COLS
    c = Index Mod NUM_COLS
    Index = r * NUM_COLS + c

    If Text1(Index).ForeColor = vbBlack Then
        Text1(Index).ForeColor = vbRed
    Else
        Text1(Index).ForeColor = vbBlack
    End If
End Sub