Macro to open multiple text files and perform operations in each one. Then copy results.

Hello, this is the situation

I´ve a folder with several text files, listed from 1 to 30. What i want is to open each file and sum all the values in the second column, then copy the result to a open excel file, the following code can do that only for one file, i think i have to implement a cycle, unfortunately i do not know how.

Note that "(1-30).txt" are all the files

Sub Sample()

        Workbooks.OpenText Filename:="C:\Users\Jorge\Desktop\Resultados\4.txt", _
        Origin:=xlMSDOS, StartRow:=1, DataType:=xlDelimited, TextQualifier:= _
        xlDoubleQuote, ConsecutiveDelimiter:=False, Tab:=True, Semicolon:=False, _
        Comma:=False, Space:=False, Other:=False, FieldInfo:=Array(Array(1, 1), _
        Array(2, 1)), DecimalSeparator:=".", ThousandsSeparator:=",", _
        TrailingMinusNumbers:=True
        Range("C2").Select
        ActiveCell.FormulaR1C1 = "=SUM(RC[-1]:R[5719]C[-1])"
        Range("C3").Select
        ActiveWindow.SmallScroll Down:=-18
        Range("C2").Select
        Selection.Copy
        Windows("Libro1.xlsm").Activate
        ActiveWindow.SmallScroll Down:=-21
        Range("A4").Select
        Selection.PasteSpecial Paste:=xlPasteValues, Operation:=xlNone, SkipBlanks _
        :=False, Transpose:=False
        Windows("4.txt").Activate
        Application.CutCopyMode = False
        Selection.ClearContents
        ActiveWindow.Close
       
End Sub

I hope someone can help, what i´ve done so far is changing the index of the file, but i know that repetitive task can be replaced esaily.

Thanks in advance

Greetings