How to shift range of cells to unify values in rows

Thanks for tips. This code works, after adding 1 variable - the counter "c1" in column A (integers from 1 to 10000), and datetime values converted to number:

    Sub shiftRange()
'
'
    Dim poc0, poc, poc2, poc3, poc4 As Long
    Dim c1Range As Range
                                             
    Set c1Range = Range("A3:A100000")
    For Each Cell In c1Range
        'if value in b3 is not equal to a3:
        If Cells(Cell.Row, 4).Value <> Cells(Cell.Row, 12).Value Then
            'if a row is not shifted already:
            If Not IsEmpty(Cells(Cell.Row, 4)) Then
                    'search in the column b3 in a range at the utmost 50 cells from the actual cell:
                    For poc = Cells(Cell.Row, 12).Row To Cell.Row + 50
                                'if a date in a1 is equal or max 1 day higher (in the case when a difference of seconds exceed to next day) then date in b1:
                                If Not IsEmpty(Cells(poc, 4)) Then
                                    If Cells(poc, 2).Value <= Cells(Cell.Row, 10).Value + 1 Then
                                        'if the time in a2 is equal or higher to time in b2:
                                        If Cells(poc, 11).Value <= Cells(Cell.Row, 3).Value Then
                                            poc2 = Cells(poc, 12).Row
                                            poc3 = poc2 - Cell.Row
                                            If poc3 > 0 Then
                                                poc4 = (Cell.Row + poc3) - 1
                                                Else: poc4 = (Cell.Row + poc3)
                                            End If
                                            'insert blank cells in the range:
                                            Range("B" & Cell.Row, "D" & poc4).Insert Shift:=xlDown
                                        End If
                                    End If
                               End If
                    Next poc
            End If
        End If
        Application.StatusBar = "Working on the row: " & Cells(Cell.Row, 1).Value
    Next
End Sub

You can indeed use basic Excel functions, in order to do this. You mention VLookup() and Lookup(), but I'm personally more in favour of the Match() function.

In order to do all this, the easiest way to start is by recording your macro, and adapt it according to your needs.
When you do that, the following will appear in your code:

Source_Cell.Copy
Destination_Cell.Paste

I would advise you to replace this by:

Destination_Cell.Value = Source_Cell.Value

The one thing I can't figure out, is the last but one point: what do you mean by "setting a row number"?

Oh, I forgot one thing: in Excel, datetime values are just integer numbers (1 stands for one day), so multiplying two values by 24*3600 and you get the number of seconds.