Spliting rows based on criterias

I am stuk and any help would be appreciated. Thank you so much in advance.

In an Excel file, there are two sheets. The first sheet consists of a row containing numbers ranging from 1 to 16. The second sheet contains multiple rows, each consisting of a minimum of 2 numbers and a maximum of 8 numbers. The first row in the second sheet may have 2, 3, 4, 5, 6, 7, or 8 numbers, and the subsequent rows may also have 2 to 8 numbers.

The objective is to compare the second sheet with the first sheet and perform the following actions based on the number of numbers in each row of the second sheet. Once a row in the first sheet is split, it should be deleted, and the comparison should be performed on the resulting split rows.

If a row in the second sheet has 2 numbers, the corresponding row in the first sheet will be split into 2 rows. Each of the split rows will contain one of the numbers from the original row.

Similarly, if a row in the second sheet has 3 numbers, the corresponding row in the first sheet will be split into 3 rows, with each split row containing one of the numbers from the original row.

I got closed with this code: 

Sub SplitRows()

    Dim firstSheet As Worksheet

    Dim secondSheet As Worksheet

    Dim firstRow As Range

    Dim secondRow As Range

    Dim splitCount As Integer

    Dim i As Integer

    Dim pasteRow As Long

    Dim numbersToSplit() As Variant

    Dim currentNumber As Variant

    Dim rowNum As Long

    ' Set the references to the first and second sheets

    Set firstSheet = ThisWorkbook.Sheets("First Sheet")

    Set secondSheet = ThisWorkbook.Sheets("Second Sheet")

    ' Clear the first sheet except the first row

    firstSheet.Rows("2:" & firstSheet.Rows.Count).ClearContents

    ' Loop through each row in the second sheet

    For Each secondRow In secondSheet.UsedRange.Rows

        ' Determine the number of numbers in the second row

        splitCount = secondRow.Cells(1).End(xlToRight).Column - secondRow.Cells(1).Column + 1

        ' Get the numbers to split from the second row

        numbersToSplit = secondRow.Resize(, splitCount).Value

        ' Loop through each number to split

        For i = 1 To splitCount

            ' Calculate the row to paste in the first sheet

            pasteRow = firstSheet.Cells(firstSheet.Rows.Count, 1).End(xlUp).Row + 1

            ' Copy the numbers from the first row

            rowNum = 1

            For Each firstRow In firstSheet.Rows(1).SpecialCells(xlCellTypeConstants)

                currentNumber = firstRow.Value

                ' Skip the current number to split

                If currentNumber <> numbersToSplit(1, i) Then

                    firstSheet.Cells(pasteRow, rowNum).Value = currentNumber

                    rowNum = rowNum + 1

                End If

            Next firstRow

            ' Increment the paste row

            pasteRow = pasteRow + 1

        Next i

    Next secondRow

End Sub

As an example, the second sheet has has three rows, the first one has two number 1 and 2 and the seond has 2 and 6 and the third row has three nu,bers 1,4 and 12 and of course in the first sheet I start only with one row which contains 16 numbers so the result should be 6 rows as follow: 

 But, when i run the code I get this result: