Hi and welcome to the forum.
If all you want to do is steps 1 to 3 then this:
Sub ImportActH()
Workbooks.Open Sheets("input").Range("e4") & "act h.xml"
Sheets("act h").Cells.Copy ThisWorkbook.Sheets("act h").Range("a1")
ActiveWorkbook.Close 0
End Sub
To clear Act H sheet 1st then:
Sub ImportActH()
Sheets("act h").Cells.ClearContents
Workbooks.Open Sheets("input").Range("e4") & "act h.xml"
Sheets("act h").Cells.Copy ThisWorkbook.Sheets("act h").Range("a1")
ActiveWorkbook.Close 0
End Sub
To chose a file from the directory specified in E2 and copy it to the relevant sheet (creating the sheet if it doesn't exist):
Sub ImportXML()
Dim fXml, fName As String, sh As Worksheet, arr
ChDir Sheets("input").Range("e2")
fXml = Application.GetOpenFilename("XML Files (*.xml),*.xml*", 1, "Select XML File", "Open", False)
If TypeName(fXml) = "Boolean" Then Exit Sub
Workbooks.Open fXml
arr = Split(fXml, "\")
fName = Left(arr(UBound(arr)), Len(arr(UBound(arr))) - 4)
With ThisWorkbook
On Error Resume Next
Set sh = .Sheets(fName)
On Error GoTo 0
If sh Is Nothing Then .Sheets.Add(After:=.Sheets("input")).Name = fName
.Sheets(fName).Cells.ClearContents
Sheets(fName).Cells.Copy .Sheets(fName).Range("a1")
End With
ActiveWorkbook.Close 0
End Sub
PS You need to add a final backslash to your file locations (C:\Users\...\OTB Report\) etc